﻿// Formatting library for C++ - the base API for char/UTF-8
//
// Copyright (c) 2012 - present, Victor Zverovich
// All rights reserved.
//
// For the license information refer to format.h.

#ifndef FMT_BASE_H_
#define FMT_BASE_H_

#if defined(FMT_IMPORT_STD) && !defined(FMT_MODULE)
#  define FMT_MODULE
#endif

#ifndef FMT_MODULE
#  include <limits.h>  // CHAR_BIT
#  include <stdio.h>   // FILE
#  include <string.h>  // strlen

// <cstddef> is also included transitively from <type_traits>.
#  include <cstddef>      // std::byte
#  include <type_traits>  // std::enable_if
#endif

// The fmt library version in the form major * 10000 + minor * 100 + patch.
#define FMT_VERSION 110002

// Detect compiler versions.
#if defined(__clang__) && !defined(__ibmxl__)
#  define FMT_CLANG_VERSION (__clang_major__ * 100 + __clang_minor__)
#else
#  define FMT_CLANG_VERSION 0
#endif
#if defined(__GNUC__) && !defined(__clang__) && !defined(__INTEL_COMPILER)
#  define FMT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
#else
#  define FMT_GCC_VERSION 0
#endif
#if defined(__ICL)
#  define FMT_ICC_VERSION __ICL
#elif defined(__INTEL_COMPILER)
#  define FMT_ICC_VERSION __INTEL_COMPILER
#else
#  define FMT_ICC_VERSION 0
#endif
#if defined(_MSC_VER)
#  define FMT_MSC_VERSION _MSC_VER
#else
#  define FMT_MSC_VERSION 0
#endif

// Detect standard library versions.
#ifdef _GLIBCXX_RELEASE
#  define FMT_GLIBCXX_RELEASE _GLIBCXX_RELEASE
#else
#  define FMT_GLIBCXX_RELEASE 0
#endif
#ifdef _LIBCPP_VERSION
#  define FMT_LIBCPP_VERSION _LIBCPP_VERSION
#else
#  define FMT_LIBCPP_VERSION 0
#endif

#ifdef _MSVC_LANG
#  define FMT_CPLUSPLUS _MSVC_LANG
#else
#  define FMT_CPLUSPLUS __cplusplus
#endif

// Detect __has_*.
#ifdef __has_feature
#  define FMT_HAS_FEATURE(x) __has_feature(x)
#else
#  define FMT_HAS_FEATURE(x) 0
#endif
#ifdef __has_include
#  define FMT_HAS_INCLUDE(x) __has_include(x)
#else
#  define FMT_HAS_INCLUDE(x) 0
#endif
#ifdef __has_cpp_attribute
#  define FMT_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
#else
#  define FMT_HAS_CPP_ATTRIBUTE(x) 0
#endif

#define FMT_HAS_CPP14_ATTRIBUTE(attribute) \
  (FMT_CPLUSPLUS >= 201402L && FMT_HAS_CPP_ATTRIBUTE(attribute))

#define FMT_HAS_CPP17_ATTRIBUTE(attribute) \
  (FMT_CPLUSPLUS >= 201703L && FMT_HAS_CPP_ATTRIBUTE(attribute))

// Detect C++14 relaxed constexpr.
#ifdef FMT_USE_CONSTEXPR
// Use the provided definition.
#elif FMT_GCC_VERSION >= 600 && FMT_CPLUSPLUS >= 201402L
// GCC only allows throw in constexpr since version 6:
// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67371.
#  define FMT_USE_CONSTEXPR 1
#elif FMT_ICC_VERSION
#  define FMT_USE_CONSTEXPR 0  // https://github.com/fmtlib/fmt/issues/1628
#elif FMT_HAS_FEATURE(cxx_relaxed_constexpr) || FMT_MSC_VERSION >= 1912
#  define FMT_USE_CONSTEXPR 1
#else
#  define FMT_USE_CONSTEXPR 0
#endif
#if FMT_USE_CONSTEXPR
#  define FMT_CONSTEXPR constexpr
#else
#  define FMT_CONSTEXPR
#endif

// Detect consteval, C++20 constexpr extensions and std::is_constant_evaluated.
#if !defined(__cpp_lib_is_constant_evaluated)
#  define FMT_USE_CONSTEVAL 0
#elif FMT_CPLUSPLUS < 201709L
#  define FMT_USE_CONSTEVAL 0
#elif FMT_GLIBCXX_RELEASE && FMT_GLIBCXX_RELEASE < 10
#  define FMT_USE_CONSTEVAL 0
#elif FMT_LIBCPP_VERSION && FMT_LIBCPP_VERSION < 10000
#  define FMT_USE_CONSTEVAL 0
#elif defined(__apple_build_version__) && __apple_build_version__ < 14000029L
#  define FMT_USE_CONSTEVAL 0  // consteval is broken in Apple clang < 14.
#elif FMT_MSC_VERSION && FMT_MSC_VERSION < 1929
#  define FMT_USE_CONSTEVAL 0  // consteval is broken in MSVC VS2019 < 16.10.
#elif defined(__cpp_consteval)
#  define FMT_USE_CONSTEVAL 1
#elif FMT_GCC_VERSION >= 1002 || FMT_CLANG_VERSION >= 1101
#  define FMT_USE_CONSTEVAL 1
#else
#  define FMT_USE_CONSTEVAL 0
#endif
#if FMT_USE_CONSTEVAL
#  define FMT_CONSTEVAL consteval
#  define FMT_CONSTEXPR20 constexpr
#else
#  define FMT_CONSTEVAL
#  define FMT_CONSTEXPR20
#endif

#if defined(FMT_USE_NONTYPE_TEMPLATE_ARGS)
// Use the provided definition.
#elif defined(__NVCOMPILER)
#  define FMT_USE_NONTYPE_TEMPLATE_ARGS 0
#elif FMT_GCC_VERSION >= 903 && FMT_CPLUSPLUS >= 201709L
#  define FMT_USE_NONTYPE_TEMPLATE_ARGS 1
#elif defined(__cpp_nontype_template_args) && \
    __cpp_nontype_template_args >= 201911L
#  define FMT_USE_NONTYPE_TEMPLATE_ARGS 1
#elif FMT_CLANG_VERSION >= 1200 && FMT_CPLUSPLUS >= 202002L
#  define FMT_USE_NONTYPE_TEMPLATE_ARGS 1
#else
#  define FMT_USE_NONTYPE_TEMPLATE_ARGS 0
#endif

#ifdef FMT_USE_CONCEPTS
// Use the provided definition.
#elif defined(__cpp_concepts)
#  define FMT_USE_CONCEPTS 1
#else
#  define FMT_USE_CONCEPTS 0
#endif

// Check if exceptions are disabled.
#ifdef FMT_EXCEPTIONS
// Use the provided definition.
#elif defined(__GNUC__) && !defined(__EXCEPTIONS)
#  define FMT_EXCEPTIONS 0
#elif FMT_MSC_VERSION && !_HAS_EXCEPTIONS
#  define FMT_EXCEPTIONS 0
#else
#  define FMT_EXCEPTIONS 1
#endif
#if FMT_EXCEPTIONS
#  define FMT_TRY try
#  define FMT_CATCH(x) catch (x)
#else
#  define FMT_TRY if (true)
#  define FMT_CATCH(x) if (false)
#endif

#if FMT_HAS_CPP17_ATTRIBUTE(fallthrough)
#  define FMT_FALLTHROUGH [[fallthrough]]
#elif defined(__clang__)
#  define FMT_FALLTHROUGH [[clang::fallthrough]]
#elif FMT_GCC_VERSION >= 700 && \
    (!defined(__EDG_VERSION__) || __EDG_VERSION__ >= 520)
#  define FMT_FALLTHROUGH [[gnu::fallthrough]]
#else
#  define FMT_FALLTHROUGH
#endif

// Disable [[noreturn]] on MSVC/NVCC because of bogus unreachable code warnings.
#if FMT_HAS_CPP_ATTRIBUTE(noreturn) && !FMT_MSC_VERSION && !defined(__NVCC__)
#  define FMT_NORETURN [[noreturn]]
#else
#  define FMT_NORETURN
#endif

#ifndef FMT_NODISCARD
#  if FMT_HAS_CPP17_ATTRIBUTE(nodiscard)
#    define FMT_NODISCARD [[nodiscard]]
#  else
#    define FMT_NODISCARD
#  endif
#endif

#ifdef FMT_DEPRECATED
// Use the provided definition.
#elif FMT_HAS_CPP14_ATTRIBUTE(deprecated)
#  define FMT_DEPRECATED [[deprecated]]
#else
#  define FMT_DEPRECATED /* deprecated */
#endif

#ifdef FMT_INLINE
// Use the provided definition.
#elif FMT_GCC_VERSION || FMT_CLANG_VERSION
#  define FMT_ALWAYS_INLINE inline __attribute__((always_inline))
#else
#  define FMT_ALWAYS_INLINE inline
#endif
// A version of FMT_INLINE to prevent code bloat in debug mode.
#ifdef NDEBUG
#  define FMT_INLINE FMT_ALWAYS_INLINE
#else
#  define FMT_INLINE inline
#endif

#if FMT_GCC_VERSION || FMT_CLANG_VERSION
#  define FMT_VISIBILITY(value) __attribute__((visibility(value)))
#else
#  define FMT_VISIBILITY(value)
#endif

#ifndef FMT_GCC_PRAGMA
// Workaround a _Pragma bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59884
// and an nvhpc warning: https://github.com/fmtlib/fmt/pull/2582.
#  if FMT_GCC_VERSION >= 504 && !defined(__NVCOMPILER)
#    define FMT_GCC_PRAGMA(arg) _Pragma(arg)
#  else
#    define FMT_GCC_PRAGMA(arg)
#  endif
#endif

// GCC < 5 requires this-> in decltype.
#if FMT_GCC_VERSION && FMT_GCC_VERSION < 500
#  define FMT_DECLTYPE_THIS this->
#else
#  define FMT_DECLTYPE_THIS
#endif

#if FMT_MSC_VERSION
#  define FMT_MSC_WARNING(...) __pragma(warning(__VA_ARGS__))
#  define FMT_UNCHECKED_ITERATOR(It) \
    using _Unchecked_type = It  // Mark iterator as checked.
#else
#  define FMT_MSC_WARNING(...)
#  define FMT_UNCHECKED_ITERATOR(It) using unchecked_type = It
#endif

#ifndef FMT_BEGIN_NAMESPACE
#  define FMT_BEGIN_NAMESPACE \
    namespace fmt {           \
    inline namespace v11 {
#  define FMT_END_NAMESPACE \
    }                       \
    }
#endif

#ifndef FMT_EXPORT
#  define FMT_EXPORT
#  define FMT_BEGIN_EXPORT
#  define FMT_END_EXPORT
#endif

#if !defined(FMT_HEADER_ONLY) && defined(_WIN32)
#  if defined(FMT_LIB_EXPORT)
#    define FMT_API __declspec(dllexport)
#  elif defined(FMT_SHARED)
#    define FMT_API __declspec(dllimport)
#  endif
#elif defined(FMT_LIB_EXPORT) || defined(FMT_SHARED)
#  define FMT_API FMT_VISIBILITY("default")
#endif
#ifndef FMT_API
#  define FMT_API
#endif

#ifndef FMT_UNICODE
#  define FMT_UNICODE 1
#endif

// Check if rtti is available.
#ifndef FMT_USE_RTTI
// __RTTI is for EDG compilers. _CPPRTTI is for MSVC.
#  if defined(__GXX_RTTI) || FMT_HAS_FEATURE(cxx_rtti) || defined(_CPPRTTI) || \
      defined(__INTEL_RTTI__) || defined(__RTTI)
#    define FMT_USE_RTTI 1
#  else
#    define FMT_USE_RTTI 0
#  endif
#endif

#define FMT_FWD(...) static_cast<decltype(__VA_ARGS__)&&>(__VA_ARGS__)

// Enable minimal optimizations for more compact code in debug mode.
FMT_GCC_PRAGMA("GCC push_options")
#if !defined(__OPTIMIZE__) && !defined(__CUDACC__)
FMT_GCC_PRAGMA("GCC optimize(\"Og\")")
#endif

FMT_BEGIN_NAMESPACE

// Implementations of enable_if_t and other metafunctions for older systems.
template <bool B, typename T = void>
using enable_if_t = typename std::enable_if<B, T>::type;
template <bool B, typename T, typename F>
using conditional_t = typename std::conditional<B, T, F>::type;
template <bool B> using bool_constant = std::integral_constant<bool, B>;
template <typename T>
using remove_reference_t = typename std::remove_reference<T>::type;
template <typename T>
using remove_const_t = typename std::remove_const<T>::type;
template <typename T>
using remove_cvref_t = typename std::remove_cv<remove_reference_t<T>>::type;
template <typename T> struct type_identity {
	using type = T;
};
template <typename T> using type_identity_t = typename type_identity<T>::type;
template <typename T>
using make_unsigned_t = typename std::make_unsigned<T>::type;
template <typename T>
using underlying_t = typename std::underlying_type<T>::type;

#if FMT_GCC_VERSION && FMT_GCC_VERSION < 500
// A workaround for gcc 4.8 to make void_t work in a SFINAE context.
template <typename...> struct void_t_impl {
	using type = void;
};
template <typename... T> using void_t = typename void_t_impl<T...>::type;
#else
template <typename...> using void_t = void;
#endif

struct monostate {
	constexpr monostate() {}
};

// An enable_if helper to be used in template parameters which results in much
// shorter symbols: https://godbolt.org/z/sWw4vP. Extra parentheses are needed
// to workaround a bug in MSVC 2019 (see #1140 and #1186).
#ifdef FMT_DOC
#  define FMT_ENABLE_IF(...)
#else
#  define FMT_ENABLE_IF(...) fmt::enable_if_t<(__VA_ARGS__), int> = 0
#endif

// This is defined in base.h instead of format.h to avoid injecting in std.
// It is a template to avoid undesirable implicit conversions to std::byte.
#ifdef __cpp_lib_byte
template <typename T, FMT_ENABLE_IF(std::is_same<T, std::byte>::value)>
inline auto format_as(T b) -> unsigned char {
	return static_cast<unsigned char>(b);
}
#endif

namespace detail {
	// Suppresses "unused variable" warnings with the method described in
	// https://herbsutter.com/2009/10/18/mailbag-shutting-up-compiler-warnings/.
	// (void)var does not work on many Intel compilers.
	template <typename... T> FMT_CONSTEXPR void ignore_unused(const T&...) {}

	constexpr auto is_constant_evaluated(bool default_value = false) noexcept
		-> bool {
		// Workaround for incompatibility between libstdc++ consteval-based
		// std::is_constant_evaluated() implementation and clang-14:
		// https://github.com/fmtlib/fmt/issues/3247.
#if FMT_CPLUSPLUS >= 202002L && FMT_GLIBCXX_RELEASE >= 12 && \
    (FMT_CLANG_VERSION >= 1400 && FMT_CLANG_VERSION < 1500)
		ignore_unused(default_value);
		return __builtin_is_constant_evaluated();
#elif defined(__cpp_lib_is_constant_evaluated)
		ignore_unused(default_value);
		return std::is_constant_evaluated();
#else
		return default_value;
#endif
	}

	// Suppresses "conditional expression is constant" warnings.
	template <typename T> constexpr auto const_check(T value) -> T { return value; }

	FMT_NORETURN FMT_API void assert_fail(const char* file, int line,
		const char* message);

#if defined(FMT_ASSERT)
	// Use the provided definition.
#elif defined(NDEBUG)
	// FMT_ASSERT is not empty to avoid -Wempty-body.
#  define FMT_ASSERT(condition, message) \
    fmt::detail::ignore_unused((condition), (message))
#else
#  define FMT_ASSERT(condition, message)                                    \
    ((condition) /* void() fails with -Winvalid-constexpr on clang 4.0.1 */ \
         ? (void)0                                                          \
         : fmt::detail::assert_fail(__FILE__, __LINE__, (message)))
#endif

#ifdef FMT_USE_INT128
	// Do nothing.
#elif defined(__SIZEOF_INT128__) && !defined(__NVCC__) && \
    !(FMT_CLANG_VERSION && FMT_MSC_VERSION)
#  define FMT_USE_INT128 1
	using int128_opt = __int128_t;  // An optional native 128-bit integer.
	using uint128_opt = __uint128_t;
	template <typename T> inline auto convert_for_visit(T value) -> T {
		return value;
	}
#else
#  define FMT_USE_INT128 0
#endif
#if !FMT_USE_INT128
	enum class int128_opt {};
	enum class uint128_opt {};
	// Reduce template instantiations.
	template <typename T> auto convert_for_visit(T) -> monostate { return {}; }
#endif

	// Casts a nonnegative integer to unsigned.
	template <typename Int>
	FMT_CONSTEXPR auto to_unsigned(Int value) -> make_unsigned_t<Int> {
		FMT_ASSERT(std::is_unsigned<Int>::value || value >= 0, "negative value");
		return static_cast<make_unsigned_t<Int>>(value);
	}

	// A heuristic to detect std::string and std::[experimental::]string_view.
	// It is mainly used to avoid dependency on <[experimental/]string_view>.
	template <typename T, typename Enable = void>
	struct is_std_string_like : std::false_type {};
	template <typename T>
	struct is_std_string_like<T, void_t<decltype(std::declval<T>().find_first_of(
		typename T::value_type(), 0))>>
		: std::is_convertible<decltype(std::declval<T>().data()),
		const typename T::value_type*> {};

	// Returns true iff the literal encoding is UTF-8.
	constexpr auto is_utf8_enabled() -> bool {
		// Avoid an MSVC sign extension bug: https://github.com/fmtlib/fmt/pull/2297.
		using uchar = unsigned char;
		return sizeof("\u00A7") == 3 && uchar("\u00A7"[0]) == 0xC2 &&
			uchar("\u00A7"[1]) == 0xA7;
	}
	constexpr auto use_utf8() -> bool {
		return !FMT_MSC_VERSION || is_utf8_enabled();
	}

	static_assert(!FMT_UNICODE || use_utf8(),
		"Unicode support requires compiling with /utf-8");

	template <typename Char> FMT_CONSTEXPR auto length(const Char* s) -> size_t {
		size_t len = 0;
		while (*s++) ++len;
		return len;
	}

	template <typename Char>
	FMT_CONSTEXPR auto compare(const Char* s1, const Char* s2, std::size_t n)
		-> int {
		if (!is_constant_evaluated() && sizeof(Char) == 1) return memcmp(s1, s2, n);
		for (; n != 0; ++s1, ++s2, --n) {
			if (*s1 < *s2) return -1;
			if (*s1 > *s2) return 1;
		}
		return 0;
	}

	namespace adl {
		using namespace std;

		template <typename Container>
		auto invoke_back_inserter()
			-> decltype(back_inserter(std::declval<Container&>()));
	}  // namespace adl

	template <typename It, typename Enable = std::true_type>
	struct is_back_insert_iterator : std::false_type {};

	template <typename It>
	struct is_back_insert_iterator<
		It, bool_constant<std::is_same<
		decltype(adl::invoke_back_inserter<typename It::container_type>()),
		It>::value>> : std::true_type {};

	// Extracts a reference to the container from *insert_iterator.
	template <typename OutputIt>
	inline auto get_container(OutputIt it) -> typename OutputIt::container_type& {
		struct accessor : OutputIt {
			accessor(OutputIt base) : OutputIt(base) {}
			using OutputIt::container;
		};
		return *accessor(it).container;
	}
}  // namespace detail

// Checks whether T is a container with contiguous storage.
template <typename T> struct is_contiguous : std::false_type {};

/**
 * An implementation of `std::basic_string_view` for pre-C++17. It provides a
 * subset of the API. `fmt::basic_string_view` is used for format strings even
 * if `std::basic_string_view` is available to prevent issues when a library is
 * compiled with a different `-std` option than the client code (which is not
 * recommended).
 */
FMT_EXPORT
template <typename Char> class basic_string_view {
private:
	const Char* data_;
	size_t size_;

public:
	using value_type = Char;
	using iterator = const Char*;

	constexpr basic_string_view() noexcept : data_(nullptr), size_(0) {}

	/// Constructs a string reference object from a C string and a size.
	constexpr basic_string_view(const Char* s, size_t count) noexcept
		: data_(s), size_(count) {}

	constexpr basic_string_view(std::nullptr_t) = delete;

	/// Constructs a string reference object from a C string.
	FMT_CONSTEXPR20
		basic_string_view(const Char* s)
		: data_(s),
		size_(detail::const_check(std::is_same<Char, char>::value &&
			!detail::is_constant_evaluated(false))
			? strlen(reinterpret_cast<const char*>(s))
			: detail::length(s)) {}

	/// Constructs a string reference from a `std::basic_string` or a
	/// `std::basic_string_view` object.
	template <typename S,
		FMT_ENABLE_IF(detail::is_std_string_like<S>::value&& std::is_same<
			typename S::value_type, Char>::value)>
	FMT_CONSTEXPR basic_string_view(const S& s) noexcept
		: data_(s.data()), size_(s.size()) {}

	/// Returns a pointer to the string data.
	constexpr auto data() const noexcept -> const Char* { return data_; }

	/// Returns the string size.
	constexpr auto size() const noexcept -> size_t { return size_; }

	constexpr auto begin() const noexcept -> iterator { return data_; }
	constexpr auto end() const noexcept -> iterator { return data_ + size_; }

	constexpr auto operator[](size_t pos) const noexcept -> const Char& {
		return data_[pos];
	}

	FMT_CONSTEXPR void remove_prefix(size_t n) noexcept {
		data_ += n;
		size_ -= n;
	}

	FMT_CONSTEXPR auto starts_with(basic_string_view<Char> sv) const noexcept
		-> bool {
		return size_ >= sv.size_ && detail::compare(data_, sv.data_, sv.size_) == 0;
	}
	FMT_CONSTEXPR auto starts_with(Char c) const noexcept -> bool {
		return size_ >= 1 && *data_ == c;
	}
	FMT_CONSTEXPR auto starts_with(const Char* s) const -> bool {
		return starts_with(basic_string_view<Char>(s));
	}

	// Lexicographically compare this string reference to other.
	FMT_CONSTEXPR auto compare(basic_string_view other) const -> int {
		size_t str_size = size_ < other.size_ ? size_ : other.size_;
		int result = detail::compare(data_, other.data_, str_size);
		if (result == 0)
			result = size_ == other.size_ ? 0 : (size_ < other.size_ ? -1 : 1);
		return result;
	}

	FMT_CONSTEXPR friend auto operator==(basic_string_view lhs,
		basic_string_view rhs) -> bool {
		return lhs.compare(rhs) == 0;
	}
	friend auto operator!=(basic_string_view lhs, basic_string_view rhs) -> bool {
		return lhs.compare(rhs) != 0;
	}
	friend auto operator<(basic_string_view lhs, basic_string_view rhs) -> bool {
		return lhs.compare(rhs) < 0;
	}
	friend auto operator<=(basic_string_view lhs, basic_string_view rhs) -> bool {
		return lhs.compare(rhs) <= 0;
	}
	friend auto operator>(basic_string_view lhs, basic_string_view rhs) -> bool {
		return lhs.compare(rhs) > 0;
	}
	friend auto operator>=(basic_string_view lhs, basic_string_view rhs) -> bool {
		return lhs.compare(rhs) >= 0;
	}
};

FMT_EXPORT
using string_view = basic_string_view<char>;

/// Specifies if `T` is a character type. Can be specialized by users.
FMT_EXPORT
template <typename T> struct is_char : std::false_type {};
template <> struct is_char<char> : std::true_type {};

namespace detail {

	// Constructs fmt::basic_string_view<Char> from types implicitly convertible
	// to it, deducing Char. Explicitly convertible types such as the ones returned
	// from FMT_STRING are intentionally excluded.
	template <typename Char, FMT_ENABLE_IF(is_char<Char>::value)>
	constexpr auto to_string_view(const Char* s) -> basic_string_view<Char> {
		return s;
	}
	template <typename T, FMT_ENABLE_IF(is_std_string_like<T>::value)>
	constexpr auto to_string_view(const T& s)
		-> basic_string_view<typename T::value_type> {
		return s;
	}
	template <typename Char>
	constexpr auto to_string_view(basic_string_view<Char> s)
		-> basic_string_view<Char> {
		return s;
	}

	template <typename T, typename Enable = void>
	struct has_to_string_view : std::false_type {};
	// detail:: is intentional since to_string_view is not an extension point.
	template <typename T>
	struct has_to_string_view<
		T, void_t<decltype(detail::to_string_view(std::declval<T>()))>>
		: std::true_type {};

	template <typename Char, Char... C> struct string_literal {
		static constexpr Char value[sizeof...(C)] = { C... };
		constexpr operator basic_string_view<Char>() const {
			return { value, sizeof...(C) };
		}
	};
#if FMT_CPLUSPLUS < 201703L
	template <typename Char, Char... C>
	constexpr Char string_literal<Char, C...>::value[sizeof...(C)];
#endif

	enum class type {
		none_type,
		// Integer types should go first,
		int_type,
		uint_type,
		long_long_type,
		ulong_long_type,
		int128_type,
		uint128_type,
		bool_type,
		char_type,
		last_integer_type = char_type,
		// followed by floating-point types.
		float_type,
		double_type,
		long_double_type,
		last_numeric_type = long_double_type,
		cstring_type,
		string_type,
		pointer_type,
		custom_type
	};

	// Maps core type T to the corresponding type enum constant.
	template <typename T, typename Char>
	struct type_constant : std::integral_constant<type, type::custom_type> {};

#define FMT_TYPE_CONSTANT(Type, constant) \
  template <typename Char>                \
  struct type_constant<Type, Char>        \
      : std::integral_constant<type, type::constant> {}

	FMT_TYPE_CONSTANT(int, int_type);
	FMT_TYPE_CONSTANT(unsigned, uint_type);
	FMT_TYPE_CONSTANT(long long, long_long_type);
	FMT_TYPE_CONSTANT(unsigned long long, ulong_long_type);
	FMT_TYPE_CONSTANT(int128_opt, int128_type);
	FMT_TYPE_CONSTANT(uint128_opt, uint128_type);
	FMT_TYPE_CONSTANT(bool, bool_type);
	FMT_TYPE_CONSTANT(Char, char_type);
	FMT_TYPE_CONSTANT(float, float_type);
	FMT_TYPE_CONSTANT(double, double_type);
	FMT_TYPE_CONSTANT(long double, long_double_type);
	FMT_TYPE_CONSTANT(const Char*, cstring_type);
	FMT_TYPE_CONSTANT(basic_string_view<Char>, string_type);
	FMT_TYPE_CONSTANT(const void*, pointer_type);

	constexpr auto is_integral_type(type t) -> bool {
		return t > type::none_type && t <= type::last_integer_type;
	}
	constexpr auto is_arithmetic_type(type t) -> bool {
		return t > type::none_type && t <= type::last_numeric_type;
	}

	constexpr auto set(type rhs) -> int { return 1 << static_cast<int>(rhs); }
	constexpr auto in(type t, int set) -> bool {
		return ((set >> static_cast<int>(t)) & 1) != 0;
	}

	// Bitsets of types.
	enum {
		sint_set =
		set(type::int_type) | set(type::long_long_type) | set(type::int128_type),
		uint_set = set(type::uint_type) | set(type::ulong_long_type) |
		set(type::uint128_type),
		bool_set = set(type::bool_type),
		char_set = set(type::char_type),
		float_set = set(type::float_type) | set(type::double_type) |
		set(type::long_double_type),
		string_set = set(type::string_type),
		cstring_set = set(type::cstring_type),
		pointer_set = set(type::pointer_type)
	};
}  // namespace detail

/// Reports a format error at compile time or, via a `format_error` exception,
/// at runtime.
// This function is intentionally not constexpr to give a compile-time error.
FMT_NORETURN FMT_API void report_error(const char* message);

FMT_DEPRECATED FMT_NORETURN inline void throw_format_error(
	const char* message) {
	report_error(message);
}

/// String's character (code unit) type.
template <typename S,
	typename V = decltype(detail::to_string_view(std::declval<S>()))>
using char_t = typename V::value_type;

/**
 * Parsing context consisting of a format string range being parsed and an
 * argument counter for automatic indexing.
 * You can use the `format_parse_context` type alias for `char` instead.
 */
FMT_EXPORT
template <typename Char> class basic_format_parse_context {
private:
	basic_string_view<Char> format_str_;
	int next_arg_id_;

	FMT_CONSTEXPR void do_check_arg_id(int id);

public:
	using char_type = Char;
	using iterator = const Char*;

	explicit constexpr basic_format_parse_context(
		basic_string_view<Char> format_str, int next_arg_id = 0)
		: format_str_(format_str), next_arg_id_(next_arg_id) {}

	/// Returns an iterator to the beginning of the format string range being
	/// parsed.
	constexpr auto begin() const noexcept -> iterator {
		return format_str_.begin();
	}

	/// Returns an iterator past the end of the format string range being parsed.
	constexpr auto end() const noexcept -> iterator { return format_str_.end(); }

	/// Advances the begin iterator to `it`.
	FMT_CONSTEXPR void advance_to(iterator it) {
		format_str_.remove_prefix(detail::to_unsigned(it - begin()));
	}

	/// Reports an error if using the manual argument indexing; otherwise returns
	/// the next argument index and switches to the automatic indexing.
	FMT_CONSTEXPR auto next_arg_id() -> int {
		if (next_arg_id_ < 0) {
			report_error("cannot switch from manual to automatic argument indexing");
			return 0;
		}
		int id = next_arg_id_++;
		do_check_arg_id(id);
		return id;
	}

	/// Reports an error if using the automatic argument indexing; otherwise
	/// switches to the manual indexing.
	FMT_CONSTEXPR void check_arg_id(int id) {
		if (next_arg_id_ > 0) {
			report_error("cannot switch from automatic to manual argument indexing");
			return;
		}
		next_arg_id_ = -1;
		do_check_arg_id(id);
	}
	FMT_CONSTEXPR void check_arg_id(basic_string_view<Char>) {
		next_arg_id_ = -1;
	}
	FMT_CONSTEXPR void check_dynamic_spec(int arg_id);
};

FMT_EXPORT
using format_parse_context = basic_format_parse_context<char>;

namespace detail {
	// A parse context with extra data used only in compile-time checks.
	template <typename Char>
	class compile_parse_context : public basic_format_parse_context<Char> {
	private:
		int num_args_;
		const type* types_;
		using base = basic_format_parse_context<Char>;

	public:
		explicit FMT_CONSTEXPR compile_parse_context(
			basic_string_view<Char> format_str, int num_args, const type* types,
			int next_arg_id = 0)
			: base(format_str, next_arg_id), num_args_(num_args), types_(types) {}

		constexpr auto num_args() const -> int { return num_args_; }
		constexpr auto arg_type(int id) const -> type { return types_[id]; }

		FMT_CONSTEXPR auto next_arg_id() -> int {
			int id = base::next_arg_id();
			if (id >= num_args_) report_error("argument not found");
			return id;
		}

		FMT_CONSTEXPR void check_arg_id(int id) {
			base::check_arg_id(id);
			if (id >= num_args_) report_error("argument not found");
		}
		using base::check_arg_id;

		FMT_CONSTEXPR void check_dynamic_spec(int arg_id) {
			detail::ignore_unused(arg_id);
			if (arg_id < num_args_ && types_ && !is_integral_type(types_[arg_id]))
				report_error("width/precision is not integer");
		}
	};

	/// A contiguous memory buffer with an optional growing ability. It is an
	/// internal class and shouldn't be used directly, only via `memory_buffer`.
	template <typename T> class buffer {
	private:
		T* ptr_;
		size_t size_;
		size_t capacity_;

		using grow_fun = void (*)(buffer& buf, size_t capacity);
		grow_fun grow_;

	protected:
		// Don't initialize ptr_ since it is not accessed to save a few cycles.
		FMT_MSC_WARNING(suppress : 26495)
			FMT_CONSTEXPR20 buffer(grow_fun grow, size_t sz) noexcept
			: size_(sz), capacity_(sz), grow_(grow) {}

		constexpr buffer(grow_fun grow, T* p = nullptr, size_t sz = 0,
			size_t cap = 0) noexcept
			: ptr_(p), size_(sz), capacity_(cap), grow_(grow) {}

		FMT_CONSTEXPR20 ~buffer() = default;
		buffer(buffer&&) = default;

		/// Sets the buffer data and capacity.
		FMT_CONSTEXPR void set(T* buf_data, size_t buf_capacity) noexcept {
			ptr_ = buf_data;
			capacity_ = buf_capacity;
		}

	public:
		using value_type = T;
		using const_reference = const T&;

		buffer(const buffer&) = delete;
		void operator=(const buffer&) = delete;

		auto begin() noexcept -> T* { return ptr_; }
		auto end() noexcept -> T* { return ptr_ + size_; }

		auto begin() const noexcept -> const T* { return ptr_; }
		auto end() const noexcept -> const T* { return ptr_ + size_; }

		/// Returns the size of this buffer.
		constexpr auto size() const noexcept -> size_t { return size_; }

		/// Returns the capacity of this buffer.
		constexpr auto capacity() const noexcept -> size_t { return capacity_; }

		/// Returns a pointer to the buffer data (not null-terminated).
		FMT_CONSTEXPR auto data() noexcept -> T* { return ptr_; }
		FMT_CONSTEXPR auto data() const noexcept -> const T* { return ptr_; }

		/// Clears this buffer.
		void clear() { size_ = 0; }

		// Tries resizing the buffer to contain `count` elements. If T is a POD type
		// the new elements may not be initialized.
		FMT_CONSTEXPR void try_resize(size_t count) {
			try_reserve(count);
			size_ = count <= capacity_ ? count : capacity_;
		}

		// Tries increasing the buffer capacity to `new_capacity`. It can increase the
		// capacity by a smaller amount than requested but guarantees there is space
		// for at least one additional element either by increasing the capacity or by
		// flushing the buffer if it is full.
		FMT_CONSTEXPR void try_reserve(size_t new_capacity) {
			if (new_capacity > capacity_) grow_(*this, new_capacity);
		}

		FMT_CONSTEXPR void push_back(const T& value) {
			try_reserve(size_ + 1);
			ptr_[size_++] = value;
		}

		/// Appends data to the end of the buffer.
		template <typename U> void append(const U* begin, const U* end) {
			while (begin != end) {
				auto count = to_unsigned(end - begin);
				try_reserve(size_ + count);
				auto free_cap = capacity_ - size_;
				if (free_cap < count) count = free_cap;
				// A loop is faster than memcpy on small sizes.
				T* out = ptr_ + size_;
				for (size_t i = 0; i < count; ++i) out[i] = begin[i];
				size_ += count;
				begin += count;
			}
		}

		template <typename Idx> FMT_CONSTEXPR auto operator[](Idx index) -> T& {
			return ptr_[index];
		}
		template <typename Idx>
		FMT_CONSTEXPR auto operator[](Idx index) const -> const T& {
			return ptr_[index];
		}
	};

	struct buffer_traits {
		explicit buffer_traits(size_t) {}
		auto count() const -> size_t { return 0; }
		auto limit(size_t size) -> size_t { return size; }
	};

	class fixed_buffer_traits {
	private:
		size_t count_ = 0;
		size_t limit_;

	public:
		explicit fixed_buffer_traits(size_t limit) : limit_(limit) {}
		auto count() const -> size_t { return count_; }
		auto limit(size_t size) -> size_t {
			size_t n = limit_ > count_ ? limit_ - count_ : 0;
			count_ += size;
			return size < n ? size : n;
		}
	};

	// A buffer that writes to an output iterator when flushed.
	template <typename OutputIt, typename T, typename Traits = buffer_traits>
	class iterator_buffer : public Traits, public buffer<T> {
	private:
		OutputIt out_;
		enum { buffer_size = 256 };
		T data_[buffer_size];

		static FMT_CONSTEXPR void grow(buffer<T>& buf, size_t) {
			if (buf.size() == buffer_size) static_cast<iterator_buffer&>(buf).flush();
		}

		void flush() {
			auto size = this->size();
			this->clear();
			const T* begin = data_;
			const T* end = begin + this->limit(size);
			while (begin != end) *out_++ = *begin++;
		}

	public:
		explicit iterator_buffer(OutputIt out, size_t n = buffer_size)
			: Traits(n), buffer<T>(grow, data_, 0, buffer_size), out_(out) {}
		iterator_buffer(iterator_buffer&& other) noexcept
			: Traits(other),
			buffer<T>(grow, data_, 0, buffer_size),
			out_(other.out_) {}
		~iterator_buffer() {
			// Don't crash if flush fails during unwinding.
			FMT_TRY{ flush(); }
				FMT_CATCH(...) {}
		}

		auto out() -> OutputIt {
			flush();
			return out_;
		}
		auto count() const -> size_t { return Traits::count() + this->size(); }
	};

	template <typename T>
	class iterator_buffer<T*, T, fixed_buffer_traits> : public fixed_buffer_traits,
		public buffer<T> {
	private:
		T* out_;
		enum { buffer_size = 256 };
		T data_[buffer_size];

		static FMT_CONSTEXPR void grow(buffer<T>& buf, size_t) {
			if (buf.size() == buf.capacity())
				static_cast<iterator_buffer&>(buf).flush();
		}

		void flush() {
			size_t n = this->limit(this->size());
			if (this->data() == out_) {
				out_ += n;
				this->set(data_, buffer_size);
			}
			this->clear();
		}

	public:
		explicit iterator_buffer(T* out, size_t n = buffer_size)
			: fixed_buffer_traits(n), buffer<T>(grow, out, 0, n), out_(out) {}
		iterator_buffer(iterator_buffer&& other) noexcept
			: fixed_buffer_traits(other),
			buffer<T>(static_cast<iterator_buffer&&>(other)),
			out_(other.out_) {
			if (this->data() != out_) {
				this->set(data_, buffer_size);
				this->clear();
			}
		}
		~iterator_buffer() { flush(); }

		auto out() -> T* {
			flush();
			return out_;
		}
		auto count() const -> size_t {
			return fixed_buffer_traits::count() + this->size();
		}
	};

	template <typename T> class iterator_buffer<T*, T> : public buffer<T> {
	public:
		explicit iterator_buffer(T* out, size_t = 0)
			: buffer<T>([](buffer<T>&, size_t) {}, out, 0, ~size_t()) {}

		auto out() -> T* { return &*this->end(); }
	};

	// A buffer that writes to a container with the contiguous storage.
	template <typename OutputIt>
	class iterator_buffer<
		OutputIt,
		enable_if_t<detail::is_back_insert_iterator<OutputIt>::value&&
		is_contiguous<typename OutputIt::container_type>::value,
		typename OutputIt::container_type::value_type>>
		: public buffer<typename OutputIt::container_type::value_type> {
	private:
		using container_type = typename OutputIt::container_type;
		using value_type = typename container_type::value_type;
		container_type& container_;

		static FMT_CONSTEXPR void grow(buffer<value_type>& buf, size_t capacity) {
			auto& self = static_cast<iterator_buffer&>(buf);
			self.container_.resize(capacity);
			self.set(&self.container_[0], capacity);
		}

	public:
		explicit iterator_buffer(container_type& c)
			: buffer<value_type>(grow, c.size()), container_(c) {}
		explicit iterator_buffer(OutputIt out, size_t = 0)
			: iterator_buffer(get_container(out)) {}

		auto out() -> OutputIt { return back_inserter(container_); }
	};

	// A buffer that counts the number of code units written discarding the output.
	template <typename T = char> class counting_buffer : public buffer<T> {
	private:
		enum { buffer_size = 256 };
		T data_[buffer_size];
		size_t count_ = 0;

		static FMT_CONSTEXPR void grow(buffer<T>& buf, size_t) {
			if (buf.size() != buffer_size) return;
			static_cast<counting_buffer&>(buf).count_ += buf.size();
			buf.clear();
		}

	public:
		counting_buffer() : buffer<T>(grow, data_, 0, buffer_size) {}

		auto count() -> size_t { return count_ + this->size(); }
	};
}  // namespace detail

template <typename Char>
FMT_CONSTEXPR void basic_format_parse_context<Char>::do_check_arg_id(int id) {
	// Argument id is only checked at compile-time during parsing because
	// formatting has its own validation.
	if (detail::is_constant_evaluated() &&
		(!FMT_GCC_VERSION || FMT_GCC_VERSION >= 1200)) {
		using context = detail::compile_parse_context<Char>;
		if (id >= static_cast<context*>(this)->num_args())
			report_error("argument not found");
	}
}

template <typename Char>
FMT_CONSTEXPR void basic_format_parse_context<Char>::check_dynamic_spec(
	int arg_id) {
	if (detail::is_constant_evaluated() &&
		(!FMT_GCC_VERSION || FMT_GCC_VERSION >= 1200)) {
		using context = detail::compile_parse_context<Char>;
		static_cast<context*>(this)->check_dynamic_spec(arg_id);
	}
}

FMT_EXPORT template <typename Context> class basic_format_arg;
FMT_EXPORT template <typename Context> class basic_format_args;
FMT_EXPORT template <typename Context> class dynamic_format_arg_store;

// A formatter for objects of type T.
FMT_EXPORT
template <typename T, typename Char = char, typename Enable = void>
struct formatter {
	// A deleted default constructor indicates a disabled formatter.
	formatter() = delete;
};

// Specifies if T has an enabled formatter specialization. A type can be
// formattable even if it doesn't have a formatter e.g. via a conversion.
template <typename T, typename Context>
using has_formatter =
std::is_constructible<typename Context::template formatter_type<T>>;

// An output iterator that appends to a buffer. It is used instead of
// back_insert_iterator to reduce symbol sizes and avoid <iterator> dependency.
template <typename T> class basic_appender {
private:
	detail::buffer<T>* buffer_;

	friend auto get_container(basic_appender app) -> detail::buffer<T>& {
		return *app.buffer_;
	}

public:
	using iterator_category = int;
	using value_type = T;
	using difference_type = ptrdiff_t;
	using pointer = T*;
	using reference = T&;
	using container_type = detail::buffer<T>;
	FMT_UNCHECKED_ITERATOR(basic_appender);

	FMT_CONSTEXPR basic_appender(detail::buffer<T>& buf) : buffer_(&buf) {}

	auto operator=(T c) -> basic_appender& {
		buffer_->push_back(c);
		return *this;
	}
	auto operator*() -> basic_appender& { return *this; }
	auto operator++() -> basic_appender& { return *this; }
	auto operator++(int) -> basic_appender { return *this; }
};

using appender = basic_appender<char>;

namespace detail {
	template <typename T>
	struct is_back_insert_iterator<basic_appender<T>> : std::true_type {};

	template <typename T, typename Enable = void>
	struct locking : std::true_type {};
	template <typename T>
	struct locking<T, void_t<typename formatter<remove_cvref_t<T>>::nonlocking>>
		: std::false_type {};

	template <typename T = int> FMT_CONSTEXPR inline auto is_locking() -> bool {
		return locking<T>::value;
	}
	template <typename T1, typename T2, typename... Tail>
	FMT_CONSTEXPR inline auto is_locking() -> bool {
		return locking<T1>::value || is_locking<T2, Tail...>();
	}

	// An optimized version of std::copy with the output value type (T).
	template <typename T, typename InputIt, typename OutputIt,
		FMT_ENABLE_IF(is_back_insert_iterator<OutputIt>::value)>
	auto copy(InputIt begin, InputIt end, OutputIt out) -> OutputIt {
		get_container(out).append(begin, end);
		return out;
	}

	template <typename T, typename InputIt, typename OutputIt,
		FMT_ENABLE_IF(!is_back_insert_iterator<OutputIt>::value)>
	FMT_CONSTEXPR auto copy(InputIt begin, InputIt end, OutputIt out) -> OutputIt {
		while (begin != end) *out++ = static_cast<T>(*begin++);
		return out;
	}

	template <typename T, typename V, typename OutputIt>
	FMT_CONSTEXPR auto copy(basic_string_view<V> s, OutputIt out) -> OutputIt {
		return copy<T>(s.begin(), s.end(), out);
	}

	template <typename Context, typename T>
	constexpr auto has_const_formatter_impl(T*)
		-> decltype(typename Context::template formatter_type<T>().format(
			std::declval<const T&>(), std::declval<Context&>()),
			true) {
		return true;
	}
	template <typename Context>
	constexpr auto has_const_formatter_impl(...) -> bool {
		return false;
	}
	template <typename T, typename Context>
	constexpr auto has_const_formatter() -> bool {
		return has_const_formatter_impl<Context>(static_cast<T*>(nullptr));
	}

	template <typename It, typename Enable = std::true_type>
	struct is_buffer_appender : std::false_type {};
	template <typename It>
	struct is_buffer_appender<
		It, bool_constant<
		is_back_insert_iterator<It>::value&&
		std::is_base_of<buffer<typename It::container_type::value_type>,
		typename It::container_type>::value>>
		: std::true_type {};

	// Maps an output iterator to a buffer.
	template <typename T, typename OutputIt,
		FMT_ENABLE_IF(!is_buffer_appender<OutputIt>::value)>
	auto get_buffer(OutputIt out) -> iterator_buffer<OutputIt, T> {
		return iterator_buffer<OutputIt, T>(out);
	}
	template <typename T, typename OutputIt,
		FMT_ENABLE_IF(is_buffer_appender<OutputIt>::value)>
	auto get_buffer(OutputIt out) -> buffer<T>& {
		return get_container(out);
	}

	template <typename Buf, typename OutputIt>
	auto get_iterator(Buf& buf, OutputIt) -> decltype(buf.out()) {
		return buf.out();
	}
	template <typename T, typename OutputIt>
	auto get_iterator(buffer<T>&, OutputIt out) -> OutputIt {
		return out;
	}

	struct view {};

	template <typename Char, typename T> struct named_arg : view {
		const Char* name;
		const T& value;
		named_arg(const Char* n, const T& v) : name(n), value(v) {}
	};

	template <typename Char> struct named_arg_info {
		const Char* name;
		int id;
	};

	template <typename T> struct is_named_arg : std::false_type {};
	template <typename T> struct is_statically_named_arg : std::false_type {};

	template <typename T, typename Char>
	struct is_named_arg<named_arg<Char, T>> : std::true_type {};

	template <bool B = false> constexpr auto count() -> size_t { return B ? 1 : 0; }
	template <bool B1, bool B2, bool... Tail> constexpr auto count() -> size_t {
		return (B1 ? 1 : 0) + count<B2, Tail...>();
	}

	template <typename... Args> constexpr auto count_named_args() -> size_t {
		return count<is_named_arg<Args>::value...>();
	}

	template <typename... Args>
	constexpr auto count_statically_named_args() -> size_t {
		return count<is_statically_named_arg<Args>::value...>();
	}

	struct unformattable {};
	struct unformattable_char : unformattable {};
	struct unformattable_pointer : unformattable {};

	template <typename Char> struct string_value {
		const Char* data;
		size_t size;
	};

	template <typename Char> struct named_arg_value {
		const named_arg_info<Char>* data;
		size_t size;
	};

	template <typename Context> struct custom_value {
		using parse_context = typename Context::parse_context_type;
		void* value;
		void (*format)(void* arg, parse_context& parse_ctx, Context& ctx);
	};

	// A formatting argument value.
	template <typename Context> class value {
	public:
		using char_type = typename Context::char_type;

		union {
			monostate no_value;
			int int_value;
			unsigned uint_value;
			long long long_long_value;
			unsigned long long ulong_long_value;
			int128_opt int128_value;
			uint128_opt uint128_value;
			bool bool_value;
			char_type char_value;
			float float_value;
			double double_value;
			long double long_double_value;
			const void* pointer;
			string_value<char_type> string;
			custom_value<Context> custom;
			named_arg_value<char_type> named_args;
		};

		constexpr FMT_ALWAYS_INLINE value() : no_value() {}
		constexpr FMT_ALWAYS_INLINE value(int val) : int_value(val) {}
		constexpr FMT_ALWAYS_INLINE value(unsigned val) : uint_value(val) {}
		constexpr FMT_ALWAYS_INLINE value(long long val) : long_long_value(val) {}
		constexpr FMT_ALWAYS_INLINE value(unsigned long long val)
			: ulong_long_value(val) {}
		FMT_ALWAYS_INLINE value(int128_opt val) : int128_value(val) {}
		FMT_ALWAYS_INLINE value(uint128_opt val) : uint128_value(val) {}
		constexpr FMT_ALWAYS_INLINE value(float val) : float_value(val) {}
		constexpr FMT_ALWAYS_INLINE value(double val) : double_value(val) {}
		FMT_ALWAYS_INLINE value(long double val) : long_double_value(val) {}
		constexpr FMT_ALWAYS_INLINE value(bool val) : bool_value(val) {}
		constexpr FMT_ALWAYS_INLINE value(char_type val) : char_value(val) {}
		FMT_CONSTEXPR FMT_ALWAYS_INLINE value(const char_type* val) {
			string.data = val;
			if (is_constant_evaluated()) string.size = {};
		}
		FMT_CONSTEXPR FMT_ALWAYS_INLINE value(basic_string_view<char_type> val) {
			string.data = val.data();
			string.size = val.size();
		}
		FMT_ALWAYS_INLINE value(const void* val) : pointer(val) {}
		FMT_ALWAYS_INLINE value(const named_arg_info<char_type>* args, size_t size)
			: named_args{ args, size } {}

		template <typename T> FMT_CONSTEXPR20 FMT_ALWAYS_INLINE value(T& val) {
			using value_type = remove_const_t<T>;
			// T may overload operator& e.g. std::vector<bool>::reference in libc++.
#if defined(__cpp_if_constexpr)
			if constexpr (std::is_same<decltype(&val), T*>::value)
				custom.value = const_cast<value_type*>(&val);
#endif
			if (!is_constant_evaluated())
				custom.value = const_cast<char*>(&reinterpret_cast<const char&>(val));
			// Get the formatter type through the context to allow different contexts
			// have different extension points, e.g. `formatter<T>` for `format` and
			// `printf_formatter<T>` for `printf`.
			custom.format = format_custom_arg<
				value_type, typename Context::template formatter_type<value_type>>;
		}
		value(unformattable);
		value(unformattable_char);
		value(unformattable_pointer);

	private:
		// Formats an argument of a custom type, such as a user-defined class.
		template <typename T, typename Formatter>
		static void format_custom_arg(void* arg,
			typename Context::parse_context_type& parse_ctx,
			Context& ctx) {
			auto f = Formatter();
			parse_ctx.advance_to(f.parse(parse_ctx));
			using qualified_type =
				conditional_t<has_const_formatter<T, Context>(), const T, T>;
			// format must be const for compatibility with std::format and compilation.
			const auto& cf = f;
			ctx.advance_to(cf.format(*static_cast<qualified_type*>(arg), ctx));
		}
	};

	// To minimize the number of types we need to deal with, long is translated
	// either to int or to long long depending on its size.
	enum { long_short = sizeof(long) == sizeof(int) };
	using long_type = conditional_t<long_short, int, long long>;
	using ulong_type = conditional_t<long_short, unsigned, unsigned long long>;

	template <typename T> struct format_as_result {
		template <typename U,
			FMT_ENABLE_IF(std::is_enum<U>::value || std::is_class<U>::value)>
		static auto map(U*) -> remove_cvref_t<decltype(format_as(std::declval<U>()))>;
		static auto map(...) -> void;

		using type = decltype(map(static_cast<T*>(nullptr)));
	};
	template <typename T> using format_as_t = typename format_as_result<T>::type;

	template <typename T>
	struct has_format_as
		: bool_constant<!std::is_same<format_as_t<T>, void>::value> {};

#define FMT_MAP_API FMT_CONSTEXPR FMT_ALWAYS_INLINE

	// Maps formatting arguments to core types.
	// arg_mapper reports errors by returning unformattable instead of using
	// static_assert because it's used in the is_formattable trait.
	template <typename Context> struct arg_mapper {
		using char_type = typename Context::char_type;

		FMT_MAP_API auto map(signed char val) -> int { return val; }
		FMT_MAP_API auto map(unsigned char val) -> unsigned { return val; }
		FMT_MAP_API auto map(short val) -> int { return val; }
		FMT_MAP_API auto map(unsigned short val) -> unsigned { return val; }
		FMT_MAP_API auto map(int val) -> int { return val; }
		FMT_MAP_API auto map(unsigned val) -> unsigned { return val; }
		FMT_MAP_API auto map(long val) -> long_type { return val; }
		FMT_MAP_API auto map(unsigned long val) -> ulong_type { return val; }
		FMT_MAP_API auto map(long long val) -> long long { return val; }
		FMT_MAP_API auto map(unsigned long long val) -> unsigned long long {
			return val;
		}
		FMT_MAP_API auto map(int128_opt val) -> int128_opt { return val; }
		FMT_MAP_API auto map(uint128_opt val) -> uint128_opt { return val; }
		FMT_MAP_API auto map(bool val) -> bool { return val; }

		template <typename T, FMT_ENABLE_IF(std::is_same<T, char>::value ||
			std::is_same<T, char_type>::value)>
		FMT_MAP_API auto map(T val) -> char_type {
			return val;
		}
		template <typename T, enable_if_t<(std::is_same<T, wchar_t>::value ||
#ifdef __cpp_char8_t
			std::is_same<T, char8_t>::value ||
#endif
			std::is_same<T, char16_t>::value ||
			std::is_same<T, char32_t>::value) &&
			!std::is_same<T, char_type>::value,
			int> = 0>
		FMT_MAP_API auto map(T) -> unformattable_char {
			return {};
		}

		FMT_MAP_API auto map(float val) -> float { return val; }
		FMT_MAP_API auto map(double val) -> double { return val; }
		FMT_MAP_API auto map(long double val) -> long double { return val; }

		FMT_MAP_API auto map(char_type* val) -> const char_type* { return val; }
		FMT_MAP_API auto map(const char_type* val) -> const char_type* { return val; }
		template <typename T, typename Char = char_t<T>,
			FMT_ENABLE_IF(std::is_same<Char, char_type>::value &&
				!std::is_pointer<T>::value)>
		FMT_MAP_API auto map(const T& val) -> basic_string_view<Char> {
			return to_string_view(val);
		}
		template <typename T, typename Char = char_t<T>,
			FMT_ENABLE_IF(!std::is_same<Char, char_type>::value &&
				!std::is_pointer<T>::value)>
		FMT_MAP_API auto map(const T&) -> unformattable_char {
			return {};
		}

		FMT_MAP_API auto map(void* val) -> const void* { return val; }
		FMT_MAP_API auto map(const void* val) -> const void* { return val; }
		FMT_MAP_API auto map(volatile void* val) -> const void* {
			return const_cast<const void*>(val);
		}
		FMT_MAP_API auto map(const volatile void* val) -> const void* {
			return const_cast<const void*>(val);
		}
		FMT_MAP_API auto map(std::nullptr_t val) -> const void* { return val; }

		// Use SFINAE instead of a const T* parameter to avoid a conflict with the
		// array overload.
		template <
			typename T,
			FMT_ENABLE_IF(
				std::is_pointer<T>::value || std::is_member_pointer<T>::value ||
				std::is_function<typename std::remove_pointer<T>::type>::value ||
				(std::is_array<T>::value &&
					!std::is_convertible<T, const char_type*>::value))>
		FMT_CONSTEXPR auto map(const T&) -> unformattable_pointer {
			return {};
		}

		template <typename T, std::size_t N,
			FMT_ENABLE_IF(!std::is_same<T, wchar_t>::value)>
		FMT_MAP_API auto map(const T(&values)[N]) -> const T(&)[N] {
			return values;
			}

			// Only map owning types because mapping views can be unsafe.
			template <typename T, typename U = format_as_t<T>,
			FMT_ENABLE_IF(std::is_arithmetic<U>::value)>
		FMT_MAP_API auto map(const T& val) -> decltype(FMT_DECLTYPE_THIS map(U())) {
			return map(format_as(val));
		}

		template <typename T, typename U = remove_const_t<T>>
		struct formattable : bool_constant<has_const_formatter<U, Context>() ||
			(has_formatter<U, Context>::value &&
				!std::is_const<T>::value)> {};

		template <typename T, FMT_ENABLE_IF(formattable<T>::value)>
		FMT_MAP_API auto do_map(T& val) -> T& {
			return val;
		}
		template <typename T, FMT_ENABLE_IF(!formattable<T>::value)>
		FMT_MAP_API auto do_map(T&) -> unformattable {
			return {};
		}

		// is_fundamental is used to allow formatters for extended FP types.
		template <typename T, typename U = remove_const_t<T>,
			FMT_ENABLE_IF(
				(std::is_class<U>::value || std::is_enum<U>::value ||
					std::is_union<U>::value || std::is_fundamental<U>::value) &&
				!has_to_string_view<U>::value && !is_char<U>::value &&
				!is_named_arg<U>::value && !std::is_integral<U>::value &&
				!std::is_arithmetic<format_as_t<U>>::value)>
		FMT_MAP_API auto map(T& val) -> decltype(FMT_DECLTYPE_THIS do_map(val)) {
			return do_map(val);
		}

		template <typename T, FMT_ENABLE_IF(is_named_arg<T>::value)>
		FMT_MAP_API auto map(const T& named_arg)
			-> decltype(FMT_DECLTYPE_THIS map(named_arg.value)) {
			return map(named_arg.value);
		}

		auto map(...) -> unformattable { return {}; }
	};

	// A type constant after applying arg_mapper<Context>.
	template <typename T, typename Context>
	using mapped_type_constant =
		type_constant<decltype(arg_mapper<Context>().map(std::declval<const T&>())),
		typename Context::char_type>;

	enum { packed_arg_bits = 4 };
	// Maximum number of arguments with packed types.
	enum { max_packed_args = 62 / packed_arg_bits };
	enum : unsigned long long { is_unpacked_bit = 1ULL << 63 };
	enum : unsigned long long { has_named_args_bit = 1ULL << 62 };

	template <typename It, typename T, typename Enable = void>
	struct is_output_iterator : std::false_type {};

	template <> struct is_output_iterator<appender, char> : std::true_type {};

	template <typename It, typename T>
	struct is_output_iterator<
		It, T, void_t<decltype(*std::declval<It&>()++ = std::declval<T>())>>
		: std::true_type {};

	// A type-erased reference to an std::locale to avoid a heavy <locale> include.
	class locale_ref {
	private:
		const void* locale_;  // A type-erased pointer to std::locale.

	public:
		constexpr locale_ref() : locale_(nullptr) {}
		template <typename Locale> explicit locale_ref(const Locale& loc);

		explicit operator bool() const noexcept { return locale_ != nullptr; }

		template <typename Locale> auto get() const->Locale;
	};

	template <typename> constexpr auto encode_types() -> unsigned long long {
		return 0;
	}

	template <typename Context, typename Arg, typename... Args>
	constexpr auto encode_types() -> unsigned long long {
		return static_cast<unsigned>(mapped_type_constant<Arg, Context>::value) |
			(encode_types<Context, Args...>() << packed_arg_bits);
	}

	template <typename Context, typename... T, size_t NUM_ARGS = sizeof...(T)>
	constexpr unsigned long long make_descriptor() {
		return NUM_ARGS <= max_packed_args ? encode_types<Context, T...>()
			: is_unpacked_bit | NUM_ARGS;
	}

	// This type is intentionally undefined, only used for errors.
	template <typename T, typename Char>
#if FMT_CLANG_VERSION && FMT_CLANG_VERSION <= 1500
	// https://github.com/fmtlib/fmt/issues/3796
	struct type_is_unformattable_for {
	};
#else
	struct type_is_unformattable_for;
#endif

	template <bool PACKED, typename Context, typename T, FMT_ENABLE_IF(PACKED)>
	FMT_CONSTEXPR auto make_arg(T& val) -> value<Context> {
		using arg_type = remove_cvref_t<decltype(arg_mapper<Context>().map(val))>;

		// Use enum instead of constexpr because the latter may generate code.
		enum {
			formattable_char = !std::is_same<arg_type, unformattable_char>::value
		};
		static_assert(formattable_char, "Mixing character types is disallowed.");

		// Formatting of arbitrary pointers is disallowed. If you want to format a
		// pointer cast it to `void*` or `const void*`. In particular, this forbids
		// formatting of `[const] volatile char*` printed as bool by iostreams.
		enum {
			formattable_pointer = !std::is_same<arg_type, unformattable_pointer>::value
		};
		static_assert(formattable_pointer,
			"Formatting of non-void pointers is disallowed.");

		enum { formattable = !std::is_same<arg_type, unformattable>::value };
#if defined(__cpp_if_constexpr)
		if constexpr (!formattable)
			type_is_unformattable_for<T, typename Context::char_type> _;
#endif
		static_assert(
			formattable,
			"Cannot format an argument. To make type T formattable provide a "
			"formatter<T> specialization: https://fmt.dev/latest/api.html#udt");
		return { arg_mapper<Context>().map(val) };
	}

	template <typename Context, typename T>
	FMT_CONSTEXPR auto make_arg(T& val) -> basic_format_arg<Context> {
		auto arg = basic_format_arg<Context>();
		arg.type_ = mapped_type_constant<T, Context>::value;
		arg.value_ = make_arg<true, Context>(val);
		return arg;
	}

	template <bool PACKED, typename Context, typename T, FMT_ENABLE_IF(!PACKED)>
	FMT_CONSTEXPR inline auto make_arg(T& val) -> basic_format_arg<Context> {
		return make_arg<Context>(val);
	}

	template <typename Context, size_t NUM_ARGS>
	using arg_t = conditional_t<NUM_ARGS <= max_packed_args, value<Context>,
		basic_format_arg<Context>>;

	template <typename Char, typename T, FMT_ENABLE_IF(!is_named_arg<T>::value)>
	void init_named_arg(named_arg_info<Char>*, int& arg_index, int&, const T&) {
		++arg_index;
	}
	template <typename Char, typename T, FMT_ENABLE_IF(is_named_arg<T>::value)>
	void init_named_arg(named_arg_info<Char>* named_args, int& arg_index,
		int& named_arg_index, const T& arg) {
		named_args[named_arg_index++] = { arg.name, arg_index++ };
	}

	// An array of references to arguments. It can be implicitly converted to
	// `fmt::basic_format_args` for passing into type-erased formatting functions
	// such as `fmt::vformat`.
	template <typename Context, size_t NUM_ARGS, size_t NUM_NAMED_ARGS,
		unsigned long long DESC>
	struct format_arg_store {
		// args_[0].named_args points to named_args to avoid bloating format_args.
		// +1 to workaround a bug in gcc 7.5 that causes duplicated-branches warning.
		static constexpr size_t ARGS_ARR_SIZE = 1 + (NUM_ARGS != 0 ? NUM_ARGS : +1);

		arg_t<Context, NUM_ARGS> args[ARGS_ARR_SIZE];
		named_arg_info<typename Context::char_type> named_args[NUM_NAMED_ARGS];

		template <typename... T>
		FMT_MAP_API format_arg_store(T&... values)
			: args{ {named_args, NUM_NAMED_ARGS},
				   make_arg<NUM_ARGS <= max_packed_args, Context>(values)... } {
			using dummy = int[];
			int arg_index = 0, named_arg_index = 0;
			(void)dummy {
				0,
					(init_named_arg(named_args, arg_index, named_arg_index, values), 0)...
			};
		}

		format_arg_store(format_arg_store&& rhs) {
			args[0] = { named_args, NUM_NAMED_ARGS };
			for (size_t i = 1; i < ARGS_ARR_SIZE; ++i) args[i] = rhs.args[i];
			for (size_t i = 0; i < NUM_NAMED_ARGS; ++i)
				named_args[i] = rhs.named_args[i];
		}

		format_arg_store(const format_arg_store& rhs) = delete;
		format_arg_store& operator=(const format_arg_store& rhs) = delete;
		format_arg_store& operator=(format_arg_store&& rhs) = delete;
	};

	// A specialization of format_arg_store without named arguments.
	// It is a plain struct to reduce binary size in debug mode.
	template <typename Context, size_t NUM_ARGS, unsigned long long DESC>
	struct format_arg_store<Context, NUM_ARGS, 0, DESC> {
		// +1 to workaround a bug in gcc 7.5 that causes duplicated-branches warning.
		arg_t<Context, NUM_ARGS> args[NUM_ARGS != 0 ? NUM_ARGS : +1];
	};

}  // namespace detail
FMT_BEGIN_EXPORT

// A formatting argument. Context is a template parameter for the compiled API
// where output can be unbuffered.
template <typename Context> class basic_format_arg {
private:
	detail::value<Context> value_;
	detail::type type_;

	template <typename ContextType, typename T>
	friend FMT_CONSTEXPR auto detail::make_arg(T& value)
		->basic_format_arg<ContextType>;

	friend class basic_format_args<Context>;
	friend class dynamic_format_arg_store<Context>;

	using char_type = typename Context::char_type;

	template <typename, size_t, size_t, unsigned long long>
	friend struct detail::format_arg_store;

	basic_format_arg(const detail::named_arg_info<char_type>* args, size_t size)
		: value_(args, size) {}

public:
	class handle {
	public:
		explicit handle(detail::custom_value<Context> custom) : custom_(custom) {}

		void format(typename Context::parse_context_type& parse_ctx,
			Context& ctx) const {
			custom_.format(custom_.value, parse_ctx, ctx);
		}

	private:
		detail::custom_value<Context> custom_;
	};

	constexpr basic_format_arg() : type_(detail::type::none_type) {}

	constexpr explicit operator bool() const noexcept {
		return type_ != detail::type::none_type;
	}

	auto type() const -> detail::type { return type_; }

	auto is_integral() const -> bool { return detail::is_integral_type(type_); }
	auto is_arithmetic() const -> bool {
		return detail::is_arithmetic_type(type_);
	}

	/**
	 * Visits an argument dispatching to the appropriate visit method based on
	 * the argument type. For example, if the argument type is `double` then
	 * `vis(value)` will be called with the value of type `double`.
	 */
	template <typename Visitor>
	FMT_CONSTEXPR FMT_INLINE auto visit(Visitor&& vis) const -> decltype(vis(0)) {
		switch (type_) {
		case detail::type::none_type:
			break;
		case detail::type::int_type:
			return vis(value_.int_value);
		case detail::type::uint_type:
			return vis(value_.uint_value);
		case detail::type::long_long_type:
			return vis(value_.long_long_value);
		case detail::type::ulong_long_type:
			return vis(value_.ulong_long_value);
		case detail::type::int128_type:
			return vis(detail::convert_for_visit(value_.int128_value));
		case detail::type::uint128_type:
			return vis(detail::convert_for_visit(value_.uint128_value));
		case detail::type::bool_type:
			return vis(value_.bool_value);
		case detail::type::char_type:
			return vis(value_.char_value);
		case detail::type::float_type:
			return vis(value_.float_value);
		case detail::type::double_type:
			return vis(value_.double_value);
		case detail::type::long_double_type:
			return vis(value_.long_double_value);
		case detail::type::cstring_type:
			return vis(value_.string.data);
		case detail::type::string_type:
			using sv = basic_string_view<typename Context::char_type>;
			return vis(sv(value_.string.data, value_.string.size));
		case detail::type::pointer_type:
			return vis(value_.pointer);
		case detail::type::custom_type:
			return vis(typename basic_format_arg<Context>::handle(value_.custom));
		}
		return vis(monostate());
	}

	auto format_custom(const char_type* parse_begin,
		typename Context::parse_context_type& parse_ctx,
		Context& ctx) -> bool {
		if (type_ != detail::type::custom_type) return false;
		parse_ctx.advance_to(parse_begin);
		value_.custom.format(value_.custom.value, parse_ctx, ctx);
		return true;
	}
};

template <typename Visitor, typename Context>
FMT_DEPRECATED FMT_CONSTEXPR auto visit_format_arg(
	Visitor&& vis, const basic_format_arg<Context>& arg) -> decltype(vis(0)) {
	return arg.visit(static_cast<Visitor&&>(vis));
}

/**
 * A view of a collection of formatting arguments. To avoid lifetime issues it
 * should only be used as a parameter type in type-erased functions such as
 * `vformat`:
 *
 *     void vlog(fmt::string_view fmt, fmt::format_args args);  // OK
 *     fmt::format_args args = fmt::make_format_args();  // Dangling reference
 */
template <typename Context> class basic_format_args {
public:
	using size_type = int;
	using format_arg = basic_format_arg<Context>;

private:
	// A descriptor that contains information about formatting arguments.
	// If the number of arguments is less or equal to max_packed_args then
	// argument types are passed in the descriptor. This reduces binary code size
	// per formatting function call.
	unsigned long long desc_;
	union {
		// If is_packed() returns true then argument values are stored in values_;
		// otherwise they are stored in args_. This is done to improve cache
		// locality and reduce compiled code size since storing larger objects
		// may require more code (at least on x86-64) even if the same amount of
		// data is actually copied to stack. It saves ~10% on the bloat test.
		const detail::value<Context>* values_;
		const format_arg* args_;
	};

	constexpr auto is_packed() const -> bool {
		return (desc_ & detail::is_unpacked_bit) == 0;
	}
	constexpr auto has_named_args() const -> bool {
		return (desc_ & detail::has_named_args_bit) != 0;
	}

	FMT_CONSTEXPR auto type(int index) const -> detail::type {
		int shift = index * detail::packed_arg_bits;
		unsigned int mask = (1 << detail::packed_arg_bits) - 1;
		return static_cast<detail::type>((desc_ >> shift) & mask);
	}

public:
	constexpr basic_format_args() : desc_(0), args_(nullptr) {}

	/// Constructs a `basic_format_args` object from `format_arg_store`.
	template <size_t NUM_ARGS, size_t NUM_NAMED_ARGS, unsigned long long DESC,
		FMT_ENABLE_IF(NUM_ARGS <= detail::max_packed_args)>
	constexpr FMT_ALWAYS_INLINE basic_format_args(
		const detail::format_arg_store<Context, NUM_ARGS, NUM_NAMED_ARGS, DESC>&
		store)
		: desc_(DESC), values_(store.args + (NUM_NAMED_ARGS != 0 ? 1 : 0)) {}

	template <size_t NUM_ARGS, size_t NUM_NAMED_ARGS, unsigned long long DESC,
		FMT_ENABLE_IF(NUM_ARGS > detail::max_packed_args)>
		constexpr basic_format_args(
			const detail::format_arg_store<Context, NUM_ARGS, NUM_NAMED_ARGS, DESC>&
			store)
		: desc_(DESC), args_(store.args + (NUM_NAMED_ARGS != 0 ? 1 : 0)) {}

	/// Constructs a `basic_format_args` object from `dynamic_format_arg_store`.
	constexpr basic_format_args(const dynamic_format_arg_store<Context>& store)
		: desc_(store.get_types()), args_(store.data()) {}

	/// Constructs a `basic_format_args` object from a dynamic list of arguments.
	constexpr basic_format_args(const format_arg* args, int count)
		: desc_(detail::is_unpacked_bit | detail::to_unsigned(count)),
		args_(args) {}

	/// Returns the argument with the specified id.
	FMT_CONSTEXPR auto get(int id) const -> format_arg {
		format_arg arg;
		if (!is_packed()) {
			if (id < max_size()) arg = args_[id];
			return arg;
		}
		if (static_cast<unsigned>(id) >= detail::max_packed_args) return arg;
		arg.type_ = type(id);
		if (arg.type_ == detail::type::none_type) return arg;
		arg.value_ = values_[id];
		return arg;
	}

	template <typename Char>
	auto get(basic_string_view<Char> name) const -> format_arg {
		int id = get_id(name);
		return id >= 0 ? get(id) : format_arg();
	}

	template <typename Char>
	FMT_CONSTEXPR auto get_id(basic_string_view<Char> name) const -> int {
		if (!has_named_args()) return -1;
		const auto& named_args =
			(is_packed() ? values_[-1] : args_[-1].value_).named_args;
		for (size_t i = 0; i < named_args.size; ++i) {
			if (named_args.data[i].name == name) return named_args.data[i].id;
		}
		return -1;
	}

	auto max_size() const -> int {
		unsigned long long max_packed = detail::max_packed_args;
		return static_cast<int>(is_packed() ? max_packed
			: desc_ & ~detail::is_unpacked_bit);
	}
};

// A formatting context.
class context {
private:
	appender out_;
	basic_format_args<context> args_;
	detail::locale_ref loc_;

public:
	/// The character type for the output.
	using char_type = char;

	using iterator = appender;
	using format_arg = basic_format_arg<context>;
	using parse_context_type = basic_format_parse_context<char>;
	template <typename T> using formatter_type = formatter<T, char>;

	/// Constructs a `basic_format_context` object. References to the arguments
	/// are stored in the object so make sure they have appropriate lifetimes.
	FMT_CONSTEXPR context(iterator out, basic_format_args<context> ctx_args,
		detail::locale_ref loc = {})
		: out_(out), args_(ctx_args), loc_(loc) {}
	context(context&&) = default;
	context(const context&) = delete;
	void operator=(const context&) = delete;

	FMT_CONSTEXPR auto arg(int id) const -> format_arg { return args_.get(id); }
	auto arg(string_view name) -> format_arg { return args_.get(name); }
	FMT_CONSTEXPR auto arg_id(string_view name) -> int {
		return args_.get_id(name);
	}
	auto args() const -> const basic_format_args<context>& { return args_; }

	// Returns an iterator to the beginning of the output range.
	FMT_CONSTEXPR auto out() -> iterator { return out_; }

	// Advances the begin iterator to `it`.
	void advance_to(iterator) {}

	FMT_CONSTEXPR auto locale() -> detail::locale_ref { return loc_; }
};

template <typename OutputIt, typename Char> class generic_context;

// Longer aliases for C++20 compatibility.
template <typename OutputIt, typename Char>
using basic_format_context =
conditional_t<std::is_same<OutputIt, appender>::value, context,
	generic_context<OutputIt, Char>>;
using format_context = context;

template <typename Char>
using buffered_context = basic_format_context<basic_appender<Char>, Char>;

template <typename T, typename Char = char>
using is_formattable = bool_constant<!std::is_base_of<
	detail::unformattable, decltype(detail::arg_mapper<buffered_context<Char>>()
		.map(std::declval<T&>()))>::value>;

#if FMT_USE_CONCEPTS
template <typename T, typename Char = char>
concept formattable = is_formattable<remove_reference_t<T>, Char>::value;
#endif

/**
 * Constructs an object that stores references to arguments and can be
 * implicitly converted to `format_args`. `Context` can be omitted in which case
 * it defaults to `format_context`. See `arg` for lifetime considerations.
 */
 // Take arguments by lvalue references to avoid some lifetime issues, e.g.
 //   auto args = make_format_args(std::string());
template <typename Context = format_context, typename... T,
	size_t NUM_ARGS = sizeof...(T),
	size_t NUM_NAMED_ARGS = detail::count_named_args<T...>(),
	unsigned long long DESC = detail::make_descriptor<Context, T...>(),
	FMT_ENABLE_IF(NUM_NAMED_ARGS == 0)>
constexpr FMT_ALWAYS_INLINE auto make_format_args(T&... args)
-> detail::format_arg_store<Context, NUM_ARGS, 0, DESC> {
	return { {detail::make_arg<NUM_ARGS <= detail::max_packed_args, Context>(
		args)...} };
}

#ifndef FMT_DOC
template <typename Context = format_context, typename... T,
	size_t NUM_NAMED_ARGS = detail::count_named_args<T...>(),
	unsigned long long DESC =
	detail::make_descriptor<Context, T...>() |
	static_cast<unsigned long long>(detail::has_named_args_bit),
	FMT_ENABLE_IF(NUM_NAMED_ARGS != 0)>
constexpr auto make_format_args(T&... args)
-> detail::format_arg_store<Context, sizeof...(T), NUM_NAMED_ARGS, DESC> {
	return { args... };
}
#endif

/**
 * Returns a named argument to be used in a formatting function.
 * It should only be used in a call to a formatting function or
 * `dynamic_format_arg_store::push_back`.
 *
 * **Example**:
 *
 *     fmt::print("The answer is {answer}.", fmt::arg("answer", 42));
 */
template <typename Char, typename T>
inline auto arg(const Char* name, const T& arg) -> detail::named_arg<Char, T> {
	static_assert(!detail::is_named_arg<T>(), "nested named arguments");
	return { name, arg };
}
FMT_END_EXPORT

/// An alias for `basic_format_args<format_context>`.
// A separate type would result in shorter symbols but break ABI compatibility
// between clang and gcc on ARM (#1919).
FMT_EXPORT using format_args = basic_format_args<format_context>;

// We cannot use enum classes as bit fields because of a gcc bug, so we put them
// in namespaces instead (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61414).
// Additionally, if an underlying type is specified, older gcc incorrectly warns
// that the type is too small. Both bugs are fixed in gcc 9.3.
#if FMT_GCC_VERSION && FMT_GCC_VERSION < 903
#  define FMT_ENUM_UNDERLYING_TYPE(type)
#else
#  define FMT_ENUM_UNDERLYING_TYPE(type) : type
#endif
namespace align {
	enum type FMT_ENUM_UNDERLYING_TYPE(unsigned char) {
		none, left, right, center,
			numeric
	};
}
using align_t = align::type;
namespace sign {
	enum type FMT_ENUM_UNDERLYING_TYPE(unsigned char) { none, minus, plus, space };
}
using sign_t = sign::type;

namespace detail {

	template <typename Char>
	using unsigned_char = typename conditional_t<std::is_integral<Char>::value,
		std::make_unsigned<Char>,
		type_identity<unsigned>>::type;

	// Character (code unit) type is erased to prevent template bloat.
	struct fill_t {
	private:
		enum { max_size = 4 };
		char data_[max_size] = { ' ' };
		unsigned char size_ = 1;

	public:
		template <typename Char>
		FMT_CONSTEXPR void operator=(basic_string_view<Char> s) {
			auto size = s.size();
			size_ = static_cast<unsigned char>(size);
			if (size == 1) {
				unsigned uchar = static_cast<unsigned_char<Char>>(s[0]);
				data_[0] = static_cast<char>(uchar);
				data_[1] = static_cast<char>(uchar >> 8);
				return;
			}
			FMT_ASSERT(size <= max_size, "invalid fill");
			for (size_t i = 0; i < size; ++i) data_[i] = static_cast<char>(s[i]);
		}

		FMT_CONSTEXPR void operator=(char c) {
			data_[0] = c;
			size_ = 1;
		}

		constexpr auto size() const -> size_t { return size_; }

		template <typename Char> constexpr auto get() const -> Char {
			using uchar = unsigned char;
			return static_cast<Char>(static_cast<uchar>(data_[0]) |
				(static_cast<uchar>(data_[1]) << 8));
		}

		template <typename Char, FMT_ENABLE_IF(std::is_same<Char, char>::value)>
		constexpr auto data() const -> const Char* {
			return data_;
		}
		template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
		constexpr auto data() const -> const Char* {
			return nullptr;
		}
	};
}  // namespace detail

enum class presentation_type : unsigned char {
	// Common specifiers:
	none = 0,
	debug = 1,   // '?'
	string = 2,  // 's' (string, bool)

	// Integral, bool and character specifiers:
	dec = 3,  // 'd'
	hex,      // 'x' or 'X'
	oct,      // 'o'
	bin,      // 'b' or 'B'
	chr,      // 'c'

	// String and pointer specifiers:
	pointer = 3,  // 'p'

	// Floating-point specifiers:
	exp = 1,  // 'e' or 'E' (1 since there is no FP debug presentation)
	fixed,    // 'f' or 'F'
	general,  // 'g' or 'G'
	hexfloat  // 'a' or 'A'
};

// Format specifiers for built-in and string types.
struct format_specs {
	int width;
	int precision;
	presentation_type type;
	align_t align : 4;
	sign_t sign : 3;
	bool upper : 1;  // An uppercase version e.g. 'X' for 'x'.
	bool alt : 1;    // Alternate form ('#').
	bool localized : 1;
	detail::fill_t fill;

	constexpr format_specs()
		: width(0),
		precision(-1),
		type(presentation_type::none),
		align(align::none),
		sign(sign::none),
		upper(false),
		alt(false),
		localized(false) {}
};

namespace detail {

	enum class arg_id_kind { none, index, name };

	// An argument reference.
	template <typename Char> struct arg_ref {
		FMT_CONSTEXPR arg_ref() : kind(arg_id_kind::none), val() {}

		FMT_CONSTEXPR explicit arg_ref(int index)
			: kind(arg_id_kind::index), val(index) {}
		FMT_CONSTEXPR explicit arg_ref(basic_string_view<Char> name)
			: kind(arg_id_kind::name), val(name) {}

		FMT_CONSTEXPR auto operator=(int idx) -> arg_ref& {
			kind = arg_id_kind::index;
			val.index = idx;
			return *this;
		}

		arg_id_kind kind;
		union value {
			FMT_CONSTEXPR value(int idx = 0) : index(idx) {}
			FMT_CONSTEXPR value(basic_string_view<Char> n) : name(n) {}

			int index;
			basic_string_view<Char> name;
		} val;
	};

	// Format specifiers with width and precision resolved at formatting rather
	// than parsing time to allow reusing the same parsed specifiers with
	// different sets of arguments (precompilation of format strings).
	template <typename Char = char> struct dynamic_format_specs : format_specs {
		arg_ref<Char> width_ref;
		arg_ref<Char> precision_ref;
	};

	// Converts a character to ASCII. Returns '\0' on conversion failure.
	template <typename Char, FMT_ENABLE_IF(std::is_integral<Char>::value)>
	constexpr auto to_ascii(Char c) -> char {
		return c <= 0xff ? static_cast<char>(c) : '\0';
	}

	// Returns the number of code units in a code point or 1 on error.
	template <typename Char>
	FMT_CONSTEXPR auto code_point_length(const Char* begin) -> int {
		if (const_check(sizeof(Char) != 1)) return 1;
		auto c = static_cast<unsigned char>(*begin);
		return static_cast<int>((0x3a55000000000000ull >> (2 * (c >> 3))) & 0x3) + 1;
	}

	// Return the result via the out param to workaround gcc bug 77539.
	template <bool IS_CONSTEXPR, typename T, typename Ptr = const T*>
	FMT_CONSTEXPR auto find(Ptr first, Ptr last, T value, Ptr& out) -> bool {
		for (out = first; out != last; ++out) {
			if (*out == value) return true;
		}
		return false;
	}

	template <>
	inline auto find<false, char>(const char* first, const char* last, char value,
		const char*& out) -> bool {
		out =
			static_cast<const char*>(memchr(first, value, to_unsigned(last - first)));
		return out != nullptr;
	}

	// Parses the range [begin, end) as an unsigned integer. This function assumes
	// that the range is non-empty and the first character is a digit.
	template <typename Char>
	FMT_CONSTEXPR auto parse_nonnegative_int(const Char*& begin, const Char* end,
		int error_value) noexcept -> int {
		FMT_ASSERT(begin != end && '0' <= *begin && *begin <= '9', "");
		unsigned value = 0, prev = 0;
		auto p = begin;
		do {
			prev = value;
			value = value * 10 + unsigned(*p - '0');
			++p;
		} while (p != end && '0' <= *p && *p <= '9');
		auto num_digits = p - begin;
		begin = p;
		int digits10 = static_cast<int>(sizeof(int) * CHAR_BIT * 3 / 10);
		if (num_digits <= digits10) return static_cast<int>(value);
		// Check for overflow.
		unsigned max = INT_MAX;
		return num_digits == digits10 + 1 &&
			prev * 10ull + unsigned(p[-1] - '0') <= max
			? static_cast<int>(value)
			: error_value;
	}

	FMT_CONSTEXPR inline auto parse_align(char c) -> align_t {
		switch (c) {
		case '<':
			return align::left;
		case '>':
			return align::right;
		case '^':
			return align::center;
		}
		return align::none;
	}

	template <typename Char> constexpr auto is_name_start(Char c) -> bool {
		return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || c == '_';
	}

	template <typename Char, typename Handler>
	FMT_CONSTEXPR auto do_parse_arg_id(const Char* begin, const Char* end,
		Handler&& handler) -> const Char* {
		Char c = *begin;
		if (c >= '0' && c <= '9') {
			int index = 0;
			if (c != '0')
				index = parse_nonnegative_int(begin, end, INT_MAX);
			else
				++begin;
			if (begin == end || (*begin != '}' && *begin != ':'))
				report_error("invalid format string");
			else
				handler.on_index(index);
			return begin;
		}
		if (!is_name_start(c)) {
			report_error("invalid format string");
			return begin;
		}
		auto it = begin;
		do {
			++it;
		} while (it != end && (is_name_start(*it) || ('0' <= *it && *it <= '9')));
		handler.on_name({ begin, to_unsigned(it - begin) });
		return it;
	}

	template <typename Char, typename Handler>
	FMT_CONSTEXPR auto parse_arg_id(const Char* begin, const Char* end,
		Handler&& handler) -> const Char* {
		FMT_ASSERT(begin != end, "");
		Char c = *begin;
		if (c != '}' && c != ':') return do_parse_arg_id(begin, end, handler);
		handler.on_auto();
		return begin;
	}

	template <typename Char> struct dynamic_spec_id_handler {
		basic_format_parse_context<Char>& ctx;
		arg_ref<Char>& ref;

		FMT_CONSTEXPR void on_auto() {
			int id = ctx.next_arg_id();
			ref = arg_ref<Char>(id);
			ctx.check_dynamic_spec(id);
		}
		FMT_CONSTEXPR void on_index(int id) {
			ref = arg_ref<Char>(id);
			ctx.check_arg_id(id);
			ctx.check_dynamic_spec(id);
		}
		FMT_CONSTEXPR void on_name(basic_string_view<Char> id) {
			ref = arg_ref<Char>(id);
			ctx.check_arg_id(id);
		}
	};

	// Parses [integer | "{" [arg_id] "}"].
	template <typename Char>
	FMT_CONSTEXPR auto parse_dynamic_spec(const Char* begin, const Char* end,
		int& value, arg_ref<Char>& ref,
		basic_format_parse_context<Char>& ctx)
		-> const Char* {
		FMT_ASSERT(begin != end, "");
		if ('0' <= *begin && *begin <= '9') {
			int val = parse_nonnegative_int(begin, end, -1);
			if (val != -1)
				value = val;
			else
				report_error("number is too big");
		}
		else if (*begin == '{') {
			++begin;
			auto handler = dynamic_spec_id_handler<Char>{ ctx, ref };
			if (begin != end) begin = parse_arg_id(begin, end, handler);
			if (begin != end && *begin == '}') return ++begin;
			report_error("invalid format string");
		}
		return begin;
	}

	template <typename Char>
	FMT_CONSTEXPR auto parse_precision(const Char* begin, const Char* end,
		int& value, arg_ref<Char>& ref,
		basic_format_parse_context<Char>& ctx)
		-> const Char* {
		++begin;
		if (begin == end || *begin == '}') {
			report_error("invalid precision");
			return begin;
		}
		return parse_dynamic_spec(begin, end, value, ref, ctx);
	}

	enum class state { start, align, sign, hash, zero, width, precision, locale };

	// Parses standard format specifiers.
	template <typename Char>
	FMT_CONSTEXPR auto parse_format_specs(const Char* begin, const Char* end,
		dynamic_format_specs<Char>& specs,
		basic_format_parse_context<Char>& ctx,
		type arg_type) -> const Char* {
		auto c = '\0';
		if (end - begin > 1) {
			auto next = to_ascii(begin[1]);
			c = parse_align(next) == align::none ? to_ascii(*begin) : '\0';
		}
		else {
			if (begin == end) return begin;
			c = to_ascii(*begin);
		}

		struct {
			state current_state = state::start;
			FMT_CONSTEXPR void operator()(state s, bool valid = true) {
				if (current_state >= s || !valid)
					report_error("invalid format specifier");
				current_state = s;
			}
		} enter_state;

		using pres = presentation_type;
		constexpr auto integral_set = sint_set | uint_set | bool_set | char_set;
		struct {
			const Char*& begin;
			dynamic_format_specs<Char>& specs;
			type arg_type;

			FMT_CONSTEXPR auto operator()(pres pres_type, int set) -> const Char* {
				if (!in(arg_type, set)) {
					if (arg_type == type::none_type) return begin;
					report_error("invalid format specifier");
				}
				specs.type = pres_type;
				return begin + 1;
			}
		} parse_presentation_type{ begin, specs, arg_type };

		for (;;) {
			switch (c) {
			case '<':
			case '>':
			case '^':
				enter_state(state::align);
				specs.align = parse_align(c);
				++begin;
				break;
			case '+':
			case '-':
			case ' ':
				if (arg_type == type::none_type) return begin;
				enter_state(state::sign, in(arg_type, sint_set | float_set));
				switch (c) {
				case '+':
					specs.sign = sign::plus;
					break;
				case '-':
					specs.sign = sign::minus;
					break;
				case ' ':
					specs.sign = sign::space;
					break;
				}
				++begin;
				break;
			case '#':
				if (arg_type == type::none_type) return begin;
				enter_state(state::hash, is_arithmetic_type(arg_type));
				specs.alt = true;
				++begin;
				break;
			case '0':
				enter_state(state::zero);
				if (!is_arithmetic_type(arg_type)) {
					if (arg_type == type::none_type) return begin;
					report_error("format specifier requires numeric argument");
				}
				if (specs.align == align::none) {
					// Ignore 0 if align is specified for compatibility with std::format.
					specs.align = align::numeric;
					specs.fill = '0';
				}
				++begin;
				break;
			case '1':
			case '2':
			case '3':
			case '4':
			case '5':
			case '6':
			case '7':
			case '8':
			case '9':
			case '{':
				enter_state(state::width);
				begin = parse_dynamic_spec(begin, end, specs.width, specs.width_ref, ctx);
				break;
			case '.':
				if (arg_type == type::none_type) return begin;
				enter_state(state::precision,
					in(arg_type, float_set | string_set | cstring_set));
				begin = parse_precision(begin, end, specs.precision, specs.precision_ref,
					ctx);
				break;
			case 'L':
				if (arg_type == type::none_type) return begin;
				enter_state(state::locale, is_arithmetic_type(arg_type));
				specs.localized = true;
				++begin;
				break;
			case 'd':
				return parse_presentation_type(pres::dec, integral_set);
			case 'X':
				specs.upper = true;
				FMT_FALLTHROUGH;
			case 'x':
				return parse_presentation_type(pres::hex, integral_set);
			case 'o':
				return parse_presentation_type(pres::oct, integral_set);
			case 'B':
				specs.upper = true;
				FMT_FALLTHROUGH;
			case 'b':
				return parse_presentation_type(pres::bin, integral_set);
			case 'E':
				specs.upper = true;
				FMT_FALLTHROUGH;
			case 'e':
				return parse_presentation_type(pres::exp, float_set);
			case 'F':
				specs.upper = true;
				FMT_FALLTHROUGH;
			case 'f':
				return parse_presentation_type(pres::fixed, float_set);
			case 'G':
				specs.upper = true;
				FMT_FALLTHROUGH;
			case 'g':
				return parse_presentation_type(pres::general, float_set);
			case 'A':
				specs.upper = true;
				FMT_FALLTHROUGH;
			case 'a':
				return parse_presentation_type(pres::hexfloat, float_set);
			case 'c':
				if (arg_type == type::bool_type) report_error("invalid format specifier");
				return parse_presentation_type(pres::chr, integral_set);
			case 's':
				return parse_presentation_type(pres::string,
					bool_set | string_set | cstring_set);
			case 'p':
				return parse_presentation_type(pres::pointer, pointer_set | cstring_set);
			case '?':
				return parse_presentation_type(pres::debug,
					char_set | string_set | cstring_set);
			case '}':
				return begin;
			default: {
				if (*begin == '}') return begin;
				// Parse fill and alignment.
				auto fill_end = begin + code_point_length(begin);
				if (end - fill_end <= 0) {
					report_error("invalid format specifier");
					return begin;
				}
				if (*begin == '{') {
					report_error("invalid fill character '{'");
					return begin;
				}
				auto align = parse_align(to_ascii(*fill_end));
				enter_state(state::align, align != align::none);
				specs.fill =
					basic_string_view<Char>(begin, to_unsigned(fill_end - begin));
				specs.align = align;
				begin = fill_end + 1;
			}
			}
			if (begin == end) return begin;
			c = to_ascii(*begin);
		}
	}

	template <typename Char, typename Handler>
	FMT_CONSTEXPR auto parse_replacement_field(const Char* begin, const Char* end,
		Handler&& handler) -> const Char* {
		struct id_adapter {
			Handler& handler;
			int arg_id;

			FMT_CONSTEXPR void on_auto() { arg_id = handler.on_arg_id(); }
			FMT_CONSTEXPR void on_index(int id) { arg_id = handler.on_arg_id(id); }
			FMT_CONSTEXPR void on_name(basic_string_view<Char> id) {
				arg_id = handler.on_arg_id(id);
			}
		};

		++begin;
		if (begin == end) return handler.on_error("invalid format string"), end;
		if (*begin == '}') {
			handler.on_replacement_field(handler.on_arg_id(), begin);
		}
		else if (*begin == '{') {
			handler.on_text(begin, begin + 1);
		}
		else {
			auto adapter = id_adapter{ handler, 0 };
			begin = parse_arg_id(begin, end, adapter);
			Char c = begin != end ? *begin : Char();
			if (c == '}') {
				handler.on_replacement_field(adapter.arg_id, begin);
			}
			else if (c == ':') {
				begin = handler.on_format_specs(adapter.arg_id, begin + 1, end);
				if (begin == end || *begin != '}')
					return handler.on_error("unknown format specifier"), end;
			}
			else {
				return handler.on_error("missing '}' in format string"), end;
			}
		}
		return begin + 1;
	}

	template <bool IS_CONSTEXPR, typename Char, typename Handler>
	FMT_CONSTEXPR void parse_format_string(basic_string_view<Char> format_str,
		Handler&& handler) {
		auto begin = format_str.data();
		auto end = begin + format_str.size();
		if (end - begin < 32) {
			// Use a simple loop instead of memchr for small strings.
			const Char* p = begin;
			while (p != end) {
				auto c = *p++;
				if (c == '{') {
					handler.on_text(begin, p - 1);
					begin = p = parse_replacement_field(p - 1, end, handler);
				}
				else if (c == '}') {
					if (p == end || *p != '}')
						return handler.on_error("unmatched '}' in format string");
					handler.on_text(begin, p);
					begin = ++p;
				}
			}
			handler.on_text(begin, end);
			return;
		}
		struct writer {
			FMT_CONSTEXPR void operator()(const Char* from, const Char* to) {
				if (from == to) return;
				for (;;) {
					const Char* p = nullptr;
					if (!find<IS_CONSTEXPR>(from, to, Char('}'), p))
						return handler_.on_text(from, to);
					++p;
					if (p == to || *p != '}')
						return handler_.on_error("unmatched '}' in format string");
					handler_.on_text(from, p);
					from = p + 1;
				}
			}
			Handler& handler_;
		} write = { handler };
		while (begin != end) {
			// Doing two passes with memchr (one for '{' and another for '}') is up to
			// 2.5x faster than the naive one-pass implementation on big format strings.
			const Char* p = begin;
			if (*begin != '{' && !find<IS_CONSTEXPR>(begin + 1, end, Char('{'), p))
				return write(begin, end);
			write(begin, p);
			begin = parse_replacement_field(p, end, handler);
		}
	}

	template <typename T, bool = is_named_arg<T>::value> struct strip_named_arg {
		using type = T;
	};
	template <typename T> struct strip_named_arg<T, true> {
		using type = remove_cvref_t<decltype(T::value)>;
	};

	template <typename T, typename ParseContext>
	FMT_VISIBILITY("hidden")  // Suppress an ld warning on macOS (#3769).
		FMT_CONSTEXPR auto parse_format_specs(ParseContext& ctx)
		-> decltype(ctx.begin()) {
		using char_type = typename ParseContext::char_type;
		using context = buffered_context<char_type>;
		using mapped_type = conditional_t<
			mapped_type_constant<T, context>::value != type::custom_type,
			decltype(arg_mapper<context>().map(std::declval<const T&>())),
			typename strip_named_arg<T>::type>;
#if defined(__cpp_if_constexpr)
		if constexpr (std::is_default_constructible<
			formatter<mapped_type, char_type>>::value) {
			return formatter<mapped_type, char_type>().parse(ctx);
		}
		else {
			type_is_unformattable_for<T, char_type> _;
			return ctx.begin();
		}
#else
		return formatter<mapped_type, char_type>().parse(ctx);
#endif
	}

	// Checks char specs and returns true iff the presentation type is char-like.
	FMT_CONSTEXPR inline auto check_char_specs(const format_specs& specs) -> bool {
		if (specs.type != presentation_type::none &&
			specs.type != presentation_type::chr &&
			specs.type != presentation_type::debug) {
			return false;
		}
		if (specs.align == align::numeric || specs.sign != sign::none || specs.alt)
			report_error("invalid format specifier for char");
		return true;
	}

#if FMT_USE_NONTYPE_TEMPLATE_ARGS
	template <int N, typename T, typename... Args, typename Char>
	constexpr auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
		if constexpr (is_statically_named_arg<T>()) {
			if (name == T::name) return N;
		}
		if constexpr (sizeof...(Args) > 0)
			return get_arg_index_by_name<N + 1, Args...>(name);
		(void)name;  // Workaround an MSVC bug about "unused" parameter.
		return -1;
	}
#endif

	template <typename... Args, typename Char>
	FMT_CONSTEXPR auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
#if FMT_USE_NONTYPE_TEMPLATE_ARGS
		if constexpr (sizeof...(Args) > 0)
			return get_arg_index_by_name<0, Args...>(name);
#endif
		(void)name;
		return -1;
	}

	template <typename Char, typename... Args> class format_string_checker {
	private:
		using parse_context_type = compile_parse_context<Char>;
		static constexpr int num_args = sizeof...(Args);

		// Format specifier parsing function.
		// In the future basic_format_parse_context will replace compile_parse_context
		// here and will use is_constant_evaluated and downcasting to access the data
		// needed for compile-time checks: https://godbolt.org/z/GvWzcTjh1.
		using parse_func = const Char* (*)(parse_context_type&);

		type types_[num_args > 0 ? static_cast<size_t>(num_args) : 1];
		parse_context_type context_;
		parse_func parse_funcs_[num_args > 0 ? static_cast<size_t>(num_args) : 1];

	public:
		explicit FMT_CONSTEXPR format_string_checker(basic_string_view<Char> fmt)
			: types_{ mapped_type_constant<Args, buffered_context<Char>>::value... },
			context_(fmt, num_args, types_),
			parse_funcs_{ &parse_format_specs<Args, parse_context_type>... } {}

		FMT_CONSTEXPR void on_text(const Char*, const Char*) {}

		FMT_CONSTEXPR auto on_arg_id() -> int { return context_.next_arg_id(); }
		FMT_CONSTEXPR auto on_arg_id(int id) -> int {
			return context_.check_arg_id(id), id;
		}
		FMT_CONSTEXPR auto on_arg_id(basic_string_view<Char> id) -> int {
#if FMT_USE_NONTYPE_TEMPLATE_ARGS
			auto index = get_arg_index_by_name<Args...>(id);
			if (index < 0) on_error("named argument is not found");
			return index;
#else
			(void)id;
			on_error("compile-time checks for named arguments require C++20 support");
			return 0;
#endif
		}

		FMT_CONSTEXPR void on_replacement_field(int id, const Char* begin) {
			on_format_specs(id, begin, begin);  // Call parse() on empty specs.
		}

		FMT_CONSTEXPR auto on_format_specs(int id, const Char* begin, const Char*)
			-> const Char* {
			context_.advance_to(begin);
			// id >= 0 check is a workaround for gcc 10 bug (#2065).
			return id >= 0 && id < num_args ? parse_funcs_[id](context_) : begin;
		}

		FMT_NORETURN FMT_CONSTEXPR void on_error(const char* message) {
			report_error(message);
		}
	};

	// A base class for compile-time strings.
	struct compile_string {};

	template <typename S>
	using is_compile_string = std::is_base_of<compile_string, S>;

	// Reports a compile-time error if S is not a valid format string.
	template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
	FMT_ALWAYS_INLINE void check_format_string(const S&) {
#ifdef FMT_ENFORCE_COMPILE_STRING
		static_assert(is_compile_string<S>::value,
			"FMT_ENFORCE_COMPILE_STRING requires all format strings to use "
			"FMT_STRING.");
#endif
	}
	template <typename... Args, typename S,
		FMT_ENABLE_IF(is_compile_string<S>::value)>
	void check_format_string(S format_str) {
		using char_t = typename S::char_type;
		FMT_CONSTEXPR auto s = basic_string_view<char_t>(format_str);
		using checker = format_string_checker<char_t, remove_cvref_t<Args>...>;
		FMT_CONSTEXPR bool error = (parse_format_string<true>(s, checker(s)), true);
		ignore_unused(error);
	}

	// Report truncation to prevent silent data loss.
	inline void report_truncation(bool truncated) {
		if (truncated) report_error("output is truncated");
	}

	// Use vformat_args and avoid type_identity to keep symbols short and workaround
	// a GCC <= 4.8 bug.
	template <typename Char = char> struct vformat_args {
		using type = basic_format_args<buffered_context<Char>>;
	};
	template <> struct vformat_args<char> {
		using type = format_args;
	};

	template <typename Char>
	void vformat_to(buffer<Char>& buf, basic_string_view<Char> fmt,
		typename vformat_args<Char>::type args, locale_ref loc = {});

	FMT_API void vprint_mojibake(FILE*, string_view, format_args, bool = false);
#ifndef _WIN32
	inline void vprint_mojibake(FILE*, string_view, format_args, bool) {}
#endif

	template <typename T, typename Char, type TYPE> struct native_formatter {
	private:
		dynamic_format_specs<Char> specs_;

	public:
		using nonlocking = void;

		template <typename ParseContext>
		FMT_CONSTEXPR auto parse(ParseContext& ctx) -> const Char* {
			if (ctx.begin() == ctx.end() || *ctx.begin() == '}') return ctx.begin();
			auto end = parse_format_specs(ctx.begin(), ctx.end(), specs_, ctx, TYPE);
			if (const_check(TYPE == type::char_type)) check_char_specs(specs_);
			return end;
		}

		template <type U = TYPE,
			FMT_ENABLE_IF(U == type::string_type || U == type::cstring_type ||
				U == type::char_type)>
		FMT_CONSTEXPR void set_debug_format(bool set = true) {
			specs_.type = set ? presentation_type::debug : presentation_type::none;
		}

		template <typename FormatContext>
		FMT_CONSTEXPR auto format(const T& val, FormatContext& ctx) const
			-> decltype(ctx.out());
	};
}  // namespace detail

FMT_BEGIN_EXPORT

// A formatter specialization for natively supported types.
template <typename T, typename Char>
struct formatter<T, Char,
	enable_if_t<detail::type_constant<T, Char>::value !=
	detail::type::custom_type>>
	: detail::native_formatter<T, Char, detail::type_constant<T, Char>::value> {
};

template <typename Char = char> struct runtime_format_string {
	basic_string_view<Char> str;
};

/// A compile-time format string.
template <typename Char, typename... Args> class basic_format_string {
private:
	basic_string_view<Char> str_;

public:
	template <
		typename S,
		FMT_ENABLE_IF(
			std::is_convertible<const S&, basic_string_view<Char>>::value ||
			(detail::is_compile_string<S>::value &&
				std::is_constructible<basic_string_view<Char>, const S&>::value))>
	FMT_CONSTEVAL FMT_ALWAYS_INLINE basic_format_string(const S& s) : str_(s) {
		static_assert(
			detail::count<
			(std::is_base_of<detail::view, remove_reference_t<Args>>::value &&
				std::is_reference<Args>::value)...>() == 0,
			"passing views as lvalues is disallowed");
#if FMT_USE_CONSTEVAL
		if constexpr (detail::count_named_args<Args...>() ==
			detail::count_statically_named_args<Args...>()) {
			using checker =
				detail::format_string_checker<Char, remove_cvref_t<Args>...>;
			detail::parse_format_string<true>(str_, checker(s));
		}
#else
		detail::check_format_string<Args...>(s);
#endif
	}
	basic_format_string(runtime_format_string<Char> fmt) : str_(fmt.str) {}

	FMT_ALWAYS_INLINE operator basic_string_view<Char>() const { return str_; }
	auto get() const -> basic_string_view<Char> { return str_; }
};

#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
// Workaround broken conversion on older gcc.
template <typename...> using format_string = string_view;
inline auto runtime(string_view s) -> string_view { return s; }
#else
template <typename... Args>
using format_string = basic_format_string<char, type_identity_t<Args>...>;
/**
 * Creates a runtime format string.
 *
 * **Example**:
 *
 *     // Check format string at runtime instead of compile-time.
 *     fmt::print(fmt::runtime("{:d}"), "I am not a number");
 */
inline auto runtime(string_view s) -> runtime_format_string<> { return { {s} }; }
#endif

/// Formats a string and writes the output to `out`.
template <typename OutputIt,
	FMT_ENABLE_IF(detail::is_output_iterator<remove_cvref_t<OutputIt>,
		char>::value)>
auto vformat_to(OutputIt&& out, string_view fmt, format_args args)
-> remove_cvref_t<OutputIt> {
	auto&& buf = detail::get_buffer<char>(out);
	detail::vformat_to(buf, fmt, args, {});
	return detail::get_iterator(buf, out);
}

/**
 * Formats `args` according to specifications in `fmt`, writes the result to
 * the output iterator `out` and returns the iterator past the end of the output
 * range. `format_to` does not append a terminating null character.
 *
 * **Example**:
 *
 *     auto out = std::vector<char>();
 *     fmt::format_to(std::back_inserter(out), "{}", 42);
 */
template <typename OutputIt, typename... T,
	FMT_ENABLE_IF(detail::is_output_iterator<remove_cvref_t<OutputIt>,
		char>::value)>
FMT_INLINE auto format_to(OutputIt&& out, format_string<T...> fmt, T&&... args)
-> remove_cvref_t<OutputIt> {
	return vformat_to(FMT_FWD(out), fmt, fmt::make_format_args(args...));
}

template <typename OutputIt> struct format_to_n_result {
	/// Iterator past the end of the output range.
	OutputIt out;
	/// Total (not truncated) output size.
	size_t size;
};

template <typename OutputIt, typename... T,
	FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
auto vformat_to_n(OutputIt out, size_t n, string_view fmt, format_args args)
-> format_to_n_result<OutputIt> {
	using traits = detail::fixed_buffer_traits;
	auto buf = detail::iterator_buffer<OutputIt, char, traits>(out, n);
	detail::vformat_to(buf, fmt, args, {});
	return { buf.out(), buf.count() };
}

/**
 * Formats `args` according to specifications in `fmt`, writes up to `n`
 * characters of the result to the output iterator `out` and returns the total
 * (not truncated) output size and the iterator past the end of the output
 * range. `format_to_n` does not append a terminating null character.
 */
template <typename OutputIt, typename... T,
	FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
FMT_INLINE auto format_to_n(OutputIt out, size_t n, format_string<T...> fmt,
	T&&... args) -> format_to_n_result<OutputIt> {
	return vformat_to_n(out, n, fmt, fmt::make_format_args(args...));
}

template <typename OutputIt, typename Sentinel = OutputIt>
struct format_to_result {
	/// Iterator pointing to just after the last successful write in the range.
	OutputIt out;
	/// Specifies if the output was truncated.
	bool truncated;

	FMT_CONSTEXPR operator OutputIt& ()& {
		detail::report_truncation(truncated);
		return out;
	}
	FMT_CONSTEXPR operator const OutputIt& () const& {
		detail::report_truncation(truncated);
		return out;
	}
	FMT_CONSTEXPR operator OutputIt && ()&& {
		detail::report_truncation(truncated);
		return static_cast<OutputIt&&>(out);
	}
};

template <size_t N>
auto vformat_to(char(&out)[N], string_view fmt, format_args args)
-> format_to_result<char*> {
	auto result = vformat_to_n(out, N, fmt, args);
	return { result.out, result.size > N };
}

template <size_t N, typename... T>
FMT_INLINE auto format_to(char(&out)[N], format_string<T...> fmt, T&&... args)
-> format_to_result<char*> {
	auto result = fmt::format_to_n(out, N, fmt, static_cast<T&&>(args)...);
	return { result.out, result.size > N };
}

/// Returns the number of chars in the output of `format(fmt, args...)`.
template <typename... T>
FMT_NODISCARD FMT_INLINE auto formatted_size(format_string<T...> fmt,
	T&&... args) -> size_t {
	auto buf = detail::counting_buffer<>();
	detail::vformat_to<char>(buf, fmt, fmt::make_format_args(args...), {});
	return buf.count();
}

FMT_API void vprint(string_view fmt, format_args args);
FMT_API void vprint(FILE* f, string_view fmt, format_args args);
FMT_API void vprint_buffered(FILE* f, string_view fmt, format_args args);
FMT_API void vprintln(FILE* f, string_view fmt, format_args args);

/**
 * Formats `args` according to specifications in `fmt` and writes the output
 * to `stdout`.
 *
 * **Example**:
 *
 *     fmt::print("The answer is {}.", 42);
 */
template <typename... T>
FMT_INLINE void print(format_string<T...> fmt, T&&... args) {
	const auto& vargs = fmt::make_format_args(args...);
	if (!detail::use_utf8()) return detail::vprint_mojibake(stdout, fmt, vargs);
	return detail::is_locking<T...>() ? vprint_buffered(stdout, fmt, vargs)
		: vprint(fmt, vargs);
}

/**
 * Formats `args` according to specifications in `fmt` and writes the
 * output to the file `f`.
 *
 * **Example**:
 *
 *     fmt::print(stderr, "Don't {}!", "panic");
 */
template <typename... T>
FMT_INLINE void print(FILE* f, format_string<T...> fmt, T&&... args) {
	const auto& vargs = fmt::make_format_args(args...);
	if (!detail::use_utf8()) return detail::vprint_mojibake(f, fmt, vargs);
	return detail::is_locking<T...>() ? vprint_buffered(f, fmt, vargs)
		: vprint(f, fmt, vargs);
}

/// Formats `args` according to specifications in `fmt` and writes the output
/// to the file `f` followed by a newline.
template <typename... T>
FMT_INLINE void println(FILE* f, format_string<T...> fmt, T&&... args) {
	const auto& vargs = fmt::make_format_args(args...);
	return detail::use_utf8() ? vprintln(f, fmt, vargs)
		: detail::vprint_mojibake(f, fmt, vargs, true);
}

/// Formats `args` according to specifications in `fmt` and writes the output
/// to `stdout` followed by a newline.
template <typename... T>
FMT_INLINE void println(format_string<T...> fmt, T&&... args) {
	return fmt::println(stdout, fmt, static_cast<T&&>(args)...);
}

FMT_END_EXPORT
FMT_GCC_PRAGMA("GCC pop_options")
FMT_END_NAMESPACE

#ifdef FMT_HEADER_ONLY
#  include "format.h"
#endif
#endif  // FMT_BASE_H_
